To be clear, I am not saying the best deck that can run Treasure Cruise is Dragon.  I am just saying it has more synergy with Dragon.  Dragon is still inherently weaker than other decks.

EDIT:  Solidarity is another deck that could potentially make use of at least Dig Through Time.  I have not seen a type 1 Solidarity deck in a while though.

The Delve cards seem like they would be best in either a Careful Study based Dragon deck or a deck running a full set of Fact or Fictions.  A Fact deck would not want to run more than about two, because you would hate to Fact into 2 Delve cards, but a Dragon deck could run more since it loads the yard so fast and can filter out redundant ones.

What deck would want to support 4 Fact or Fictions?

I have some out of date experience running Enlightened Tutor in Grim Long.  I was actually already running one when it was unrestricted and I liked that that for all the reasons you mentioned.  I then tried running four and quickly found that four did not work.  Here is the issue.  Hands with one top deck Tutor are solid in fast combo decks.  This is more true now that Brainstorm is restricted so they do not compete with Brainstorm as a turn one play.  Hands with two top deck tutors are bad if your goal is to combo out turn two because the second top deck tutor basically functions as a dead draw.  Most combo decks will start with Mystical and Vampiric.  Adding the 3rd top dock tutor triples the chance you start with two and adding a fourth doubles it on top of that.  It seemed to me at the time that a total of four top deck tutors was the sweet spot, so you could run Imperial Seal and Enlightened Tutor or 2 Enlightened Tutor.

I briefly toyed with running Enlightened Tutor over Imperial Seal, but ultimately Imperial seal was better.  That Enlightened Tutor forces you to show your opponent what you tutored for is significant, especially when grabbing Black Lotus.  When playing against Long it is frequently difficult to decide whether countering Black Lotus is the correct decision, but if you opponent just Enlightened Tutored for it then it becomes much easier.

Mana Vault

So you pull out 4 Intuitions, 4 Accumulated Knowledge and 2 Fact or Fictions and add 4 Gush, 2 Jace and Twister and declare your draw engine better?
To be fair Gush is the better draw spell.  There is a reason it was restricted twice.  Still, I believe you are underestimating the power of Intuition/AK with a few Facts thrown in.  Also Snapcaster on AK for 4 is insane, while Snapcastering Gush is weak and Snapcaster cannot replay Jace.  You draw engine has advantages.  In particular it is more combolicious, but it does not gain more card advantage.

Your mana curve is "lower" but without Fastbond you rarely want to Gush before turn 3.  Meanwhile Intuition is a fine turn 2 play and Fact or Fiction can frequently be played turn 2 and almost always by turn 3.  None of these prevent me from keeping Drain mana up during my opponents main phase like a turn 3 Gush would.  Although your draw spends less mana it is actually slower.  Furthermore Intuition has great flexibility in that it can grab Force in an emergency or "win now" in the late game.

For shops you add 2 Hurkyl's which makes a huge difference, but then Tendrils can be an extra dead card in hand.  You drop the number of basics and drop 2 mana sources.  You run Duress which is fairly poor vs Shops and Mental Misstep which is close to totally dead.  You are left with Colossus, Tendrils and 2 Missteps being almost dead and Duress is super risky since fetching Sea on turn 1 is too risky when you want to get Gush mana up and waiting till later makes Duress much worse.

I have not tested your list yet, but it is not obvious to me that the draw engine or Shops matchup is better.

While the goldfishing may be similar, in practice I expect my list to play out faster because all the draw spells are somewhat redundant, while your list is more bomb oriented.  You do run more control with 12 counters including Duress and 2 Bounce.  That is two more control cards than I run.  If Doomsday Gush or other combo become popular then your list will be much better because having access to the 4 Duress + Misstep will matter more, but as is I think I would rather have the Mana Leaks which remain useful against Shops.

0 Tendrils of Agony is on purpose.  Tinker+Time Walk is the preferred win now option.  Each card is a bomb on their own (although BSC is a dead draw) and together they win now.  Also each can generate mana when going off since Walk lets you play a draw spell and take another turn and you can Tinker for Lotus in front of Yawg.
Sometimes BSC gets Swordsed by Fish which is really bad.
Beyond that if Tinker is countered twice then you are probably losing anyway.
Also hardcasting BSC is not as rare as you might think.  The draw engine is silly and 30 mana sources (including Drains + Chain) means getting double digit mana is not uncommon.

If I were running Gushbond, I would probably not run 7 Drains + Leaks.
Protecting Fastbond from Misstep would be a higher priority and would demand missteps of my own.
I would definitely not run just the changes you suggested.   A better question is why not just run a more traditional deck with a Gushbond engine.

Advantages of my list:
2 Color mana base is good for Shops
Nearly pure instant draw engine means you get Drain + Leak mana up most of the time.
Faster goldfish
Draw engine that draws more cards
11 hard counters
A control deck that is barely touched by Mental Misstep
Few card disadvantage tutors

Disadvantages of my list:
Chalice for 0+1 on turn 1 is bad.
Chalice@2 is pretty bad (No more Drain, Leaks, AKs or Snap Casters)
Wants lots of mana.
Low 1cc count means few turn 1 play when no accelerates or when Chalice@0 was dropped.

The matchup I have been losing the most sleep over is Workshops.
In particular, Hurkyl's Recall might have been wrong because Chalice@2 was already so strong.  Maybe those should be Rebuilds.

I have done a more testing and here is the list I would play right now:

5 Fetchlands
6th Fetchland or Cephalid Coliseum
4 Underground Sea
4 Island (1 Snow Covered is fine)
1 Tolarian Academy

10 Artifact Mana
1 Blightsteel Colossus

1 Yawgmoth's Will
1 Demonic Tutor
0 Vampiric Tutor

2 Snapcaster Mage
1 Tinker
1 Merchant Scroll
1 Time Walk
4 Force of Will
2 Fact or Fiction
1 Gifts Ungiven
4 Intuition (Yes 4)
1 Thirst for Knowledge
4 Accumulated Knowledge
4 Mana Drain
3 Mana Leak
1 Ancestral Recall
1 Brainstorm
1 Chain of Vapor (Not sure this is best bounce spell)
1 Mystical Tutor

Sideboard:  (Obviously meta dependant)
1 Strip Mine
4 Wasteland
3 Engineered Explosives
4 Leyline of the Void
3 Hurkyl's Recall

The loss of Thirst for Knowledge is bad and makes this deck hungry at the 3cc spot.  This partly explains 4 Intuitions.  The other factor is that Intuitioning for 2xSnapcaster + Yawg is so powerful that extra Intuitions are rarely problematic.

Fact or Fiction is a huge bomb, but it competes with Snapcaster as a lategame card and you just cannot put more than 4 in without running into too many slow hands.

I got down to 61 cards and spent a while trying to decide between Vampiric Tutor, Mana Leak #3 and Land #15.
Basically, what it comes down to Mental Misstep.  It used to be hands with Fetch/Sea + Vamp were keepable because I could Vamp for Recall on turn 1 and then run out Recall on turn 2.  Without Misstep or Misdirection to protect my own Recall, it becomes unlikely I can actually resolve Recall so Vamp just loss me card advantage and I might get stuck mana shafted.  In those situations I would much rather have a second land.
Also with only 1 Brainstorm having the extra land is more important so lands are better.
Once I ran 15 Lands I felt very comfortable with the 3rd Mana Leak.  Usually you have Land + Mox on turn 1 and when you do not you are likely to have 2 lands.  Those 2 Land, 0 Mox hands are where Drain is golden and for similar reasons Mana Leak is also strong there.

Another questionable card is Merchant Scroll.  Basically I realize that Recall is likely to get counterd, but I am okay losing so tempo and Mana Scrolling in that case and Scroll also finds the 4th AK and so many other cards.

Intuitions can function like Gifts #2-#5 in that they are win now cards in the late game.  Basically this deck develops its mana very quickly and being able to Intuition for 2xSnapcaster + Yawg is super powerful.

Coliseum obviously hurts the Stax matchup, but without only 2 Brainstorm + Thirst for Knowledge it is nice to have a 3rd way to shuffle Colossus.  Depending on the meta I would be tempted to add the 6th fetch for safety against Wasteland, but I would not add Library over Coliseum.

I have a few comments, because I have been consistently testing various Drain Tendrils lists:

#1)  Tinker/Time Walk seems like the win condition of choice to me now that we have BSC since that is a win now option.
I am not sure if Vault/Key belong in the deck or not, but I think Tinker->BSC definitely belongs.  There may be no need for an additional win condition since you can just beat with Snapcasters if need be.

#2)  Mana Leak has been working out well in terms of extra counters.  Basically I have been testing using 8-9x (Fact, Snapcaster, Mana Leak) in various combinations.  If you run 0 Spell Pierce and 0 Mental Misstep then you relevant 1cc counters are 1 Ancestral Recall and 1 Brainstorm.  If your opponent counters Mana or a top deck Tutor then celebrate.  Mana Leak is frequently available on turn 1 and thus fills the Brainstorm Gap and the vast majority of the deck is instant speed so you can keep Mana Leak up and EOT play draw spells.  Midirection is an option, but you will want to Misdirect Recall a lot and then can just Misstep their own Recall which weakens Misdirection considerably.
Against Shop, Leak is of course better than Misstep.  Leak is fairly strong against Gush decks that do not have Fastbond in play because they undevelop their mana base leaving Leak relevant the whole game rather than just the early game.

#3)  Fact or Fiction is strong in this deck.  It is a bit slow as is Snapcaster, but there is just so much synergy.  Basically Fact helps you get AKs 2,3 4 so much faster.  It loads the yard for Yawg.  It can get replayed with Snapcaster Mage.  Also you can sit with Fact mana up and either Snapcaster->(Leak or Drain) or if they play nothing on their turn EOT Fact.
  
EDIT:
#4)  I have been struggling over what to do with bounce.  I have been running just 1 Chain of Vapor.  The main advantage of this is that Chalice@1 is so awful against this deck that I rarely want to bounce it and Chain handles everything else.  Also Chain can bounce multiple Snapcasters which is strong in the late game.  The disadvantage is that there is no mass bounce vs Shops and in a BSC BSC mirror if I Chain them I get my own BSC bounced.  I could run more bounce, but then I would need to drop Mana Leaks and they have been so good.

If you run Oath, then I recommend Rasputin, Dreamweaver with Replenish and Recoup so you can Recoup Replenish.  That could potentially get This card and Bargain at once.

I have the following old decklist lying around.  (Actually I have this deck sleeved up too)

4 Forbidden Orchard
4 City Of Brass
4 Gemstone Mine
1 Barbarian Ring
1 Nomad Stadium
1 Strip Mine
4 Wasteland
4 Ancient Tomb -> Replace one of these with Mishra's Factory
1 Black Lotus -> Make this a second Factory
4 Crucible Of Worlds
4 Null Rod ->Make these 1 Vault + 3 Key
1 Blightsteel Colossus
2 Dragon Breath
1 Yawgmoth's Will
1 Demonic Tutor
1 Imperial Seal
1 Vampiric Tutor
1 Time Walk -> Make me a Grafdigger's Cage
4 Intuition
1 Ancestral Recall -> Replace with Brainstorm
4 Oath Of Druids
1 Fastbond
1 Regrowth
1 Memory's Journey
4 Argivian Find
4 Enlightened Tutor



Basically you have a ton of tutors to get Oath out or Vault/Key out or Fastbond/Crucible or get Dragon's Breath when you Oath.

In case it is not obvious, with Fastbond + Crucible out and then Strip + Stadium in yard you get infinite life.
Add Barbarian Ring and you do infinite damage. 
Add 2 Factories and you can make an infinite/infinite size Assembly Worker.

This means that if your first Oath activation fizzles or Blightsteel is in your hand, you can use your Oath activation to empty your library.
Then use Memory's Journey to put either Fastbond, Crucible or both in your library and win this turn or next turn.

The weakness of this deck is the lack of disruption.  Even with a full set of Rods, it was weak in the disruption department, but with the Vault/Key combo subbed in it only gets worse.


Along with the combos Enlightened Tutor and Intuition can find Dragon's Breath.  Basically you can ET just before you Oath to guarantee you get a Dragon Breath in the yard.  Also you can Intuition for 2 Dragon Breath and at least one will end up in the yard.

Also, if you are running maindeck Vault/Key, then adding a token Grafdigger's Cage seems really good.  It does shut off your own Oath, but you can win without Oath and having one main deck cage will make a huge difference vs dredge.

This runs nine control cards if you exclude the Jaces's which is about how many Pitch Long ran, yet it is slower.  The threat density is good, but I suspect that just running more control to help resolve Oath would be better, because once Griselbrand it out a control deck should already be WAY ahead.  Adding Rituals is mostly win more.

Ritual solves the wrong problem.  With Oath, the question is not:  "I have my Griselbrand in play.  How do I win?"
Once you have Griselbrand in play you should be able to win through control.

Instead Oath must ask the question "I have Griselbrand in my hand.  Now how do I win?"
From that perspective I suggest Mana Drain since it could potentially lead to hardcasting Griselbrand if it is in your hand, can help protect Oath and if you have Griselbrand in play it is one more Counterspell to draw.

Can someone explain Gitaxian Probe?

In my experience this card is terrible in Belcher because the mulligan is so important.  Having Gitaxian Probe in my opening hand means I must make a mulligan decision knowing only 6 cards instead of 7 and that makes my deck worse.  For this reason I do not even run Manamorphose, but at least Manamorphose fixes mana.

Also Sylvan Library is good in Belcher in general and has some synergy with Reforge the Soul since you can put it on top to use it for 2 the next turn.

It also has dissynergy since I do not want to draw a Library after a draw 7.

Also the problem with Reforge the Soul is it is hard to make the most of its alternate ability when so many of your mana sources are Sorcery speed.
Even if you are lucky enough to top deck it during your draw phase, you end up discarding a bunch of Seething Song and other sorcery speed spells.

I think the idea will mostly be to pay 5 To Wheel which is still good in a Belcher List, but it makes me terrified of counter magic.  With Warrens you are sort of uncounterable because of Storm and with Belcher you might have Welders to recur it if it is countered.  I hated having Wheel countered when I payed 3, but it was still obviously worth it, but paying 5 to have it countered is a bit scarier

I do not see Noxious Revival, Mystical Tutor or Ancestral Knowledge making this card great because of the card disadvantage.
Mystical Tutor can at least find Brainstorm to shuffle away some of these, but there will still usually be better tutor targets.

Jace seems the best use, but you need to have ways to get it out of your hand.  Imagine having 2 of these in an opening hand.
Such a hand will be challenged to even resolve Jace in the first place.

I have not tested it much recently, because once Mental Misstep was printed relying on Breakthrough and Careful Study became terrible.

So my expectation is that a lot of folks will try roguish decks with 4 of these in the main for a while which will be bad for Dredge.
Then those roguish decks will not do well, and folks will commonly run 4 in the board and frequently run 1 as a tutor target.

The 1 maindeck as a tutor target will hurt Dredge's game 1 plan so that will hurt Dredge.
The 3 in the board are less threatening than Planar Void (which RFGs your cards) and Pithing Needle (which stops your draw engine to find answers.)

Ultimately it will be a wash.

A question is if Dredge should run stuff in the main to combat the 1 Cage.  I will be looking into that.
Mental Misstep actually makes it tempting to run a blue version of Dredge.

Even without Breakthrough and Careful Study you can run Force, Misstep, Narcos, Fatestitchers and possibly the Sharuum engine which gets you to around 20 blue cards.

The first question is how good is this card? 
It does not address most draw engines.
It does address broken win conditions like Dread Return, Oath, Tinker and Yawg.
It does not address Vault/Key, which by itself makes it much weaker vs Tinker since most Tinker decks run Vault/Key.
If anything this helps a Tinker deck since this is now a viable Tinker target.
Yawg decks are used to needing to bounce a threat (or run Misstep to counter it) before going off.  This is a nice card vs Yawg, but hardly just beats them.
Oath decks run Vault/Key still, but this does shut off Oath pretty hard.
This is worse than Pithing Needle against Dredge, because this neither remove threats from the game permanently like Planar Void nor does it shut down Dredge's draw engine.  If maindecked this would have a similar effect to maindecking Pithing Needle, but I do not see large quantities of these maindecked.

What I expect the most likely use will be as a very common sideboard card to fight Oath, Dredge and Long if that ever shows up again.

Then this is strong tutor target in the main.

Along with Vault/Key the other "broken" comboes that still work are Painter/Grindstone, Helmline, Fastbond/Crucible and Salvagers Recursion.

Of those Salvagers seems best positioned to benefit.  First, Oath is what has kept Salvagers down and this card makes fighting Oath easier.

Second, Trinket Mage can fetch this card as a one of in a main deck so it fits nicely into a controlling bomberman shell.

Third, Bomberman's main combo is untouched by this card.

A second comment I would like to make is regarding Shop decks.  This card is an artifact and is sort of good with Shops.  It still does not address Vault/Key or medium sized creatures (Goyf.)

To me Ensnaring Bridge and Null Rod are natural cards to run along side this in a shop Deck, but I am not sure where to go from there.  I have been toying around with a few Turboland and Uba Stax lists with Rod, Bridge and Cage, but I have nothing yet.  The trouble for Uba Stax is that this card is a speed bump rather than a lock (like Null Brooch or Uba Lock) and speed bumps do not play well with Ensnaring Bridge since you cannot run big creatures.

Turboland in theory seems better, but in practice it is not working yet.  It recently occured to me that Bazaar/Squee might be better since it is unaffected by this card and Cage is likely to mean fewer cards that hate out Squee.

Right now, I think Bomberman is the best home for Cage, but I still hope to find something with Turboland.

Flusterstorm is an interesting idea.
The problem I see with this line of play is to play Tinker, Recall and Flusterstorm in the same turn you need 5 mana, but you are sitting on 2 (3 if you count Gush) so it is likely to be several turns before you get to 5 mana at all and even later against a deck like Landstill that actually runs mana denial.  In addition, Force of Will, Mental Misstep, Misdirection and Mindbreak Trap cost no mana.  Trap trumps your plan and even if they planned on using some combination of the other mentioned counters or even REB, Landstill is reasonably likely to to have the mana to pay through your Flusterstorm.

I agree with ELD here.  Misdirection is a threat, but it is a threat that grows as the game gets older.   There is a 20% chance that your opponent is sitting on MisD on turn 1, but wait a few turns and that probability increases dramatically.  Landstill runs more countermagic and develops its permanent mana better so the later you wait the more they are likely they are to draw into Misdirection, have mana for REB/Drain or have played a Standstill.

Gush decks are about tempo.  You want to do something now.  Delaying vs Landstill is in general a bad idea.  You are are the beatdown, not them.

Playing from the hand is good and also Ashen Ghoul has that number of creatures on top requirement which is annoying.

Another issue is that this guy can be played multiple times per turn.  Are there any cards that give you mana whenever a creatuers comes into play (Lotus Cobra of creatures?)

Seems sick with Skullclamp, but you need that Zombie.

Phyrexian Altar gives mana every time you sac a creature so these two and Bridge is infinite creatures.

So I agree with most of this post except for Mage.

The issue is resolving your Denials for card advantage.  You cannot afford to lose those counter wars.

The card that I have wanted the most in my "wildcard" spot has actually been Misdirection.

Misdirection solves the Mindbreak Trap issue.  Against Flusterstorm if you could have had Misdirection or Spell Pierce you want Misdirection.
Basically you Misdirect one copy of Flusterstorm to the other and then use the mana you would have spent on Spell Pierce to force through the last Flusterstorm and you resolve your spell.

The huge caveat is that I have been testing vs other control decks and obviously Spell Pierce is superior vs Shops.

Snapcaster Mage is week with Arcane Denials and here is why.
Snapcaster Mage is about throwing out spells and letting them get countered because you can replay them anyway.

With Arcane Denial the pain of having it countered is so bad that once I use Snapcaster Mage to get it back, it is likely to just get countered all over again and now I am down more card advantage with only a 2/1 body to show for it.  In such a case Snapcaster Mage is either lose less or possibly lose more.

If Arcane Denial resolves then I am already significantly ahead, so while Snapcaster Mage is very strong, I was already winning so it becomes a win more.  It is not that much of a win more because resolving Arcane Denial is not as bad as Resolving a Recall for your opponent, but basically it takes you from ahead, to more ahead.

What is most important is resolving that first Arcane Denial and for that Misdirection is best since it protects from Mindbreak Trap and Spell Pierce and can sort of save you from Flusterstorm.

One drawback would be the high CC interacting with Dark Confidant, but I do not run Tinker so losing life is rarely a big issue.  Adding 2 Misdirections should be fine.

The main drawback will most likely be vs Shops, because without Brainstorm, Jace or Thirst for Knowledge I cannot filter out dead cards easily.  I suppose I could try Denialing my own Misdirection, but that's not happening with any Resistor effects out.  Basically Misdirection is only useful as Force fodder.
This only affects one of the 3 games vs Shops so it might be tolerable.  The preboard Shop matchup is already suspect anyway.

The issue is Fatestitcher.  Fatestitcher also wants that Undiscovered Paradise mana and is much better.

Even post board I would rather have Fatestitcher.

I have not tested it in this deck in any number.  Would it be better than Noxious Revivial?  I realize Snapcaster Mage gives +2 card advantage compared to Noxious Revival (if you count the 2/1 body) but Noxious Revival has more synergy.

I may try that next.  I am in the early phases of testing Noxious Revival and the cards have some similarities so I may start to consider how it would be different if my Noxious Revival were a Snapcaster Mage.

Noxious Revival seems to have the most pure power.

Basically it is a "Regrowth" but it has -1 card advantage and costs 2 less and is instant speed.

Preliminary testing finds that it is solid post Yawg for putting counters on top of your library, but I think that is sort of win more.  Beyond that you can recur Recall or get back a countered Yawg.

Gut Shot has potential since you can draw at instant speed with it.

EDIT:  Noxious Revival too!

So for those who did not notice, my original post was from last May and is outdated.

Since then I have added Mental Misstep to this deck and dropped the Urza's Baubles.

Urza's Bauble became worse once Thirst was dropped.

Misstep is nice in that it protects you from Stifle and Spell Pierce (which are 3 for 1 when you trying to Denial.)

Also, you can Denial your own Mental Misstep so basically if your opponent plays a 1CC spell you can Misstep it and then if they counter your Misstep you can Denial your Misstep and Denial becomes a 3 for 1 Trade which is huge.

Denials advantages over Night's Whisper are fairly significant:
#1)   You are loading the yard for Yawg.  Basically Thirst was either +0 or +1 card advantage, but way better than Night's Whisper because it loads the yard and digs.
#2)  Digs (see above).  Basically if you believe that Arcane Denial and Mishra's Bauble suck, then you just traded your 2 worst cards for 3 new cards which is pretty awesome!
#3)  Blue
#4)  You can counter a late Bomb like Yawg/Vault/Tinker/Oath etc.
#5)  You can sort of "instant speed" it if you counter your own Misstep on purpose.
#6)  Occasional 3 for 1 trade with countered Spells.  It is very common that an opponent counters a Bob and then you just recounter your own Bob with Denial to draw 3 cards for   .
#7)  Library of Leng:  Because you draw the cards next turn you can potentially go up to a hand size of 10 during your opponent's upkeep.  This is huge after a utility Yawg.

Regarding this new proposed list:

I notice no Dark Confidants.  Those are pretty good, especially with Mindbreak Trap out there.

Empty the Warrens is very tempting.  I have tried it many times and ultimately I decided I wanted Coliseums over Volcanic Island, but it is definitely at least close to being worth it.

Opals seem shady to me with so few artifacts given the fact that you want to counter artifacts anyway.  

Chain of Vapor is very good.

I think there are too many ways to win here.  If you are already running Tinker, Vault/Key and Tez I am not sure that Warrens is needed.
Basically if you run Tinker then Thirst is good again, but also Cephalid Coliseum becomes very good so I would rather Volcanic Island be Coliseum.

If you want to keep Warrens, then maybe drop Tez and add Fact or Fiction.  I tested Fact as 3 of back when it was unrestriced and it was underwhelming.

Regarding New Weaknesses:
Mindbreak Trap is bad for sure, but it is not as bad as Stifle was because it is less prevalent than Stifle was.
This new list addresses Mindbreak Trap partly by adding Tinker, but turn 1 Mox, Probe, Denial is SUPER risky.  Turn 1 Mox, Bob is better.

Flusterstorm is also bad and makes the whole Tendrils route questionable.  Regarding Tendrils, keep in mind that it is there as a means to race more than an actual win condition.  If you just stormed for enough to win then you will probably have a 10 card hand next upkeep so even if all copies of Tendrils are Flusterstormed you still probably win the game, only you must use Bob Beats (or another win condition) instead.

I found Mana Crypt risky, but I ran Bobs so for you it is much safer.

Xantid Swarm was okay right after Spell Pierce was printed, but Mental Misstep means it is no longer good.  Xantid Swarm is pretty bad right now.

http://www.starcitygames.com/php/news/print.php?Article=12828
Becker's win through Tormod's Crypt with a Yawg Will is probably my favorite play of all time.

Dredge's game one win percentage is a function of their opponent's willingness to run disruption.

When folks complain they must dedicate half their sideboard, what they are really saying is they need not dedicate a single maindeck card to beating Dredge.

I like your analytical style of thinking!

Just in terms of theoretical power level Serum Powder is restrictable.  It is as powerful or more powerful than Timetwister.

Tangent - Unrestricting Twister could be very hard on Dredge!

Anyway I actually think that the fact that Ichorid dodges both mana Denial and counter spells is a good thing because it hurts decks that focus on hardcore mana denial or that relies on counterspells to lock you out.
Basically I consider forcing Shop decks to run creatures and have some sort of clock a good thing.
I also consider it a good thing that Dredge limits how much countermagic control can run.
The problem with Dredge is is its speed.  A dredge deck that runs Crop Rotations and Breakthroughs would be worse, but its goldfish would be just as good.  You would move towards a direction where every blue deck ran 4 Mental Misstep as Dredge hate.  Dredge might start to run Mental Misstep to protect Crop Rotation.

Then Shops would be much better off on the play, but worse off on the draw.  Basically you could Waste their turn 1 Bazaar only to watch in horror as Breakthrough on turn 2 wins it for them.  On the other hand turn 1 Resistor/Thor/Golem could lock Dredge out of its Crop Rotation.  The result is a matchup that depends more on the coinflip.

I still believe a Serum Powder Dredge list with a turn 3-5 goldfish would be the way to go.  To get there restrict Dread Return and Fatestitcher.