My creatures hit multiple decks as once better than you might think.
Wretch: Welder/Grunt/Darkblast/Ichorid/Y Will/Crucible/Threshold-Flashback-Dregde/Dragon...
Child: ToA and with Oath it can stop an army
Kataki: Stax(main reason)/Gifts/Slaver/Belcher/Any deck that wants to create a mana base with artifacts/Kills Opposing Kataki
Confidant: DO I REALLY NEED TO?
Right... they all attack different decks... meaning that each creature isn't versatile on their own... Meddling mage is effective against any deck... Child is not
Ex... I understand the power of Wretch vs. Grunt if they have to stand off... but in reality they don't very often meaning that we only look to comparative value in terms of what they attempt to do... Grunt also stops the very same decks that you are talking about... Additionally, it doesn't take mana to use its ability meaning that you can then play more threats securring a better position. If, for whatever reason, the deck you are playing against is not GY deck... then grunt can still swing in for 4 which is a much bigger threat than a wretch...
Sure, compared to one on one wretch may own Grunt... but grunt is more versatile and still hates out the decks that need to be hated out (making his overall value better)
This was just an example so don't get too hung up on it... I am merely trying to say that your creatures tend to be focused on beating different decks... Similarly, this means, that if you draw kataki, confident, and child w/o ghoul then you may have problems with ichorid b/c the only card that would help you is wretch. Similarly, if you are facing stax... sure, you may be able to turn off welder with wretch, but w/o kataki, and with a smokestack in play (common) you will eat up your resources trying to keep welder unusable and thus prevent more drops -> being unable to keep up with smokestack -> lock etc...
Obviously these are scenarios that may or may not cause overall problems since you also carry duress/therapy/extirpate but do show the fundemental flaw with what you have chosen... Sylvan and confidant are a slow draw engine (not saying that you can find better) both of which will only get you on average 1 extra card by turn 3... Assuming that you do not draw the right disruption in your hand, how do you plan on getting to the right hate card/preventing them from winning?
Additionally, besides confidant, thiese are the reasons that cards like wretch and kataki are most often seen in sideboards... they may do a better effect against the deck in question, but you trade versatility for that effect... It is better to have a slightly weaker deck that doesn't matter what creature it draws with the option of sideboarding than a deck that is hit or miss...
I understand cabal/duress/extirpate can all be strong... However, you do have limited mana availability... On average you will only have 2-3 mana for the first few turns especially w/o early draw to help even this out... If you waste/strip then you are stuck with the choice of either playing no creature, paying wretch's ability, or casting disruption in your hand only... not all three which is what your deck strongly advocates...
For Ex. lets look at therapy... If you play it turn one, then you are guessing as to what they have and will often miss. If you play it on turn 2 after you figure out what is in their hand, then you forgo a creature drop (so trading off one disruption for another)... and if you decide to play a turn 2 cabal and plan on using therapy twice then you play turn 1 duress (presumably) turn 2 cabal (trading one disruption card for another) and then turn three play a creature and sac it (thereby removing your own disruptive force)... The turn 1 play is often not that helpful. If you then try to sac a creature turn two after playing a turn 1 therapy, then you are removing two disruption cards for one of the opponents and have barely hurt them. Turn 2 play can be helpful, but only if your opponents hand allows b/c it means you have done nothing to create a clock and the effect is not static meaning they have the option of recovering much quicker at this point if they play draw spells... the turn 3 option means you are able to destroy their 3 biggest threats in hand... At the same time, you are left with very little disruption, have not been drawing cards (and will take you at least another two turns to do so) and have created no permenant damage (like a static effect)... This is not to say that removing their 3 biggest threats thus far is nothing to laugh at, butit does mean that you are for an uphill battle in terms of a resource war which they are better designed to take advantage of from this point. This all of course assumes that they do not have any disruption/do not use it which is kinda silly...
As a final note on the duresss/therapy/extirpate cards... Just because you include these cards does not make your deck as a whole viable. These cards are not unique to your deck design... If these cards are truly as powerful as you say then in reality the shell of this deck has nothing to do with the creatures involved but rather the non-creature disruption... Those same cards could be included in shop aggro, fish, Oath of Druids (therapy would be worse but you say that you tend to know their hand anyway), etc... With this in mind, the basic shell is created up of the non-creature disruption and you have to justify why your creature strategy is better than these other decks/does something unique. To this end, I truly think that you do do something unique. However, I do not think that it can do it consistently enough (b/c of versatility and draw issues that i talked about previously) as compared to what other decks have to offer... I would much rather cast turn 1 duress, turn 2 meddling mage than turn 1 duress, turn two child against an opposing dragon deck etc...
Child is the only creature for 1 mana that can delay a ToA turn 1.
I agree, but this does not mean he is viable... If you are truly afraid of ToA for 1, why not play chalice set at 0 followed up by a therapy/duress? This eliminates mana and the duress can take a dark ritual, draw spell, etc... Namely whatever they need for gas to win. This play is much stronger than playing creatures in that it prevents the opponent from performing his strategy vs. a turn 1 korlis which does not thus allowing removal to be found (every combo deck carries removal)... I think Korlis is a cool trick for sure, but what do you do against the opponent then casting an ETW for 10-12 creatures turn 1/2? you prevent damage for a turn, but w/o oath you have no way of truly competing. Since ETW is being added into a lot of ToA builds (gifts, long, etc...) Korlis seems to not be that effective anymore... It is better to prevent them from performing the way they want to than to play a card that prevents them from winning only (b/c an answer or alternative win condition will be found).
Finally, I just don't find your deck to be that resilient. Sure, Ghoul may be able to bring a creature back... but that takes a turn (during which I may win) and your creatures are not versatile. Additionally, ghoul is probably a good counter target etc... What I'm more concerned with is how do you deal with more generalized disruption.
Like your deck seems to do well in goldfish mode... but I still don't understand how you deal with opposing disruption... Chalice for 1 backed up with counters seems pretty strong... Or what if they play orb of dreams turn 1 meaning you have no mana until turn 3 since you will probably use a fetch to get the land... during that time they will definately get a huge advantage on you... What if they counter confidant so that your draw engine is shut off? (instant draw isn't hurt as bad since you get more bang for your buck and you get it now rather than having to wait for the cumulative effect). How do you then continue to apply pressure? What do you do when they play turn 1 oath (on the play) and you don't have a Korlis in hand? Do you not play creatures to stop activation? or, what if a dragon deck decides to duress you and takes wretch? your plan against dragon is now destroyed and you have to have extirpate and hope that you haven't already used it as a means of looking at their hand to make your own therapy stronger to even have a chance...
To sum up
1: Your deck is not as disruptive as you like to think:
a. resource issues/trade-offs
b. not versatile
c. limited draw/search to find key disruption and recover when disruption exhausted
2: Your disruption is not unique to your deck.
a. lack of focus (fish's focus is to disrupt and have clock... it does this with free disruption... what is yours?)
b. Other decks have a better shell than you and can still utilize the part of your deck that makes you so strong... why is your deck, as a whole, viable?
3. Your inability to deal with opposing disruption effectively.
a. Limited draw/search
b. not versatile enough