Thanks for the replies. I'll break down my thoughts on it based on card choice, card play and matchups.
Card choice1. Sensei's Divining Top - I liked Top. I liked it a lot, but it doesn't do as much as brainstorm and after the first activation, is strictly worse than Opt. For that reason, I kept 5 fetchlands to maximize it and even use Krosan Rec at times to shuffle the library. But playing it that way kept you back from maximizing your draw x's (Runes) or some other color-specific relevant play, especially Thoughtseize. One way to see it is, the deck likes to dig. In the same way that Grim Long digs with draw 7's, mine digs with Tfk and Runes. Another way to see it is in terms of card quality. I need to see new cards, not draw something I've seen the turn before. In a strict sense, pure draw gives you more choices.
2. Read the Runes - I will compare the other draw cards mentioned. Careful Study, Compulsive Research and Intuition. Careful study is a good turn 1 drop, but in playtesting, it often competed with a turn 1 Thoughtseize. I would prefer a duress-effect at turn 1 to disrupt my opponent's hand and gather intelligence rather than sculpt my hand. On turn 2, most often you already have land, land, mox at which point you could do better than cast Careful Study. A tougher call is Compulsive Research on turn 2. But, again, as with Careful Study, you often find yourself holding Tfk and you can't cast both. Also, holding back casting on your main phase turn 2, gives your opponent something to think about before casting any bomb. Again, tough call but it's a matter of priorities.
Intuition is another turn 2 card. This is my scenario: I have developed my mana base but I need 2 cards to go off (Oath, Orchard or Animate + disruption or counter w/ Tyrant in the yard). Intuition can give me 1 of those cards. I cast it, but opponent counters. All things being equal, the board retains the status quo. Scenario 2: Same board position. I cast Tfk to draw into random, likely 1 land, 2 business spells. My business spells are likely to be control + combo. If it's Thoughtseize and Animate ->GG. More likely it will be more board position. Tfk (as with Runes) is meant to draw the inevitable combo, with control backup. In that way, it plays very similarly to Gush-Bond where you draw tons of cards, establish control and then go off. I'm not saying Intuition is not good, as you will surely get the cards you need. I am just more comfortable with sufficient board control/backup before I try comboing out.
Back to Runes. It's instant, same virtue as Tfk. Getting 2 on turn 2 at instant speed vs. 3 at sorcery (Research) is a tough call, but that's on turn 2. Down the line, Runes becomes increasingly powerful and with only 2 (a conscious effort to keep them out of the opening hand), the likelihood of mana aplenty before seeing one is very high. Also, the fact that Research competes for the same spot, not with Runes, but with Tfk was a major consideration. Finally, with Tyrant out, you can practically draw your deck and win outright with Runes.
3. Flash of Insight - Flash of Insight was a major boon to the Tyrant Oath build, not by what it did in the hand, as it was a poor to mediocre tutor, but what it did when it hit the yard. Fully 60-65% of Brainfreeze kills followed a recursion of Insight with Brainfreeze in the library or put back in it by Krosan Rec. Insight even permitted you to chain Ancestral, business, Tfk, business, Fow, draw, business, etc. to practically draw your library and win even sans Brainfreeze. So strong is this play, that Smennen lamented Insight's loss in the last iterations of Tyrant Oath. Presently, Insight, is even stronger as one of the main thrusts of this build is to actually pitch things in the yard. And there hasn't been a time when I wasn't happy playing Tfk/Runes and seeing either Krosan Rec/Insight/Tyrant in hand.
Card Play1. Tfk - I've never had the problem pitching artifacts to the GY. I see this as an issue, however, if you are using Tolarian Academy.
2. Triskev - Tyrant Oath wins about 20% after the first activation. But it wins upwards of 75% of the time after the second activation on the back of Tyrant, Krosan Rec and Flash of Insight. Triskev or Triskel in the board may be a good call, however, depending on what you expect to fight against (i.e. Slaver) and you choose that approach. I would rather have an active Tyrant, however, as it can just as easily remove welders, among other things. One other interesting play with 2 Tyrants is in having two moxes and bouncing 1 of your opponent's permanents and 1 of your moxes. Rinse, repeat to remove ALL his permanents. You can't do that with Triskev.
3. Flash of Insight/Krosan Rec - I can't emphasize enough the significance of the first builds of Tyrant Oath with Krosan Rec and Flash of Insight. Those 2 cards interact so well in the GY after a successful Oath activation that the combo is strictly diminished without either one of them. In fact, I would go so far as to say that I am playing something else than Tyrant Oath combo without those cards.
4. Thoughtseize - I play this everytime I draw it, even against control. It severely disrupts your opponent, keeps them from killing you outright or paves the way for an instant during their turn. At the very least, you gather intel on what he has. The question is, whether you want to combo off or wait for FoW/Thoughtseize as backup, you usually do.
5. Mana - 16 lands, or I should say: 2 islands, 5 fetchlands and 3 underground seas were meant for: a) turn 1 thoughtseize, b) get stripped and still draw with Tfk/Runes, c) avoid getting stripped in the first place. But I did find myself holding on to Orchard if there wasn't one already in play, as this is easily the most important land. Island in the opening hand and a mox/crypt usually meant turn 1 Tfk/draw into more mana such that mana denial becomes even less of a threat.
6. Animate Dead - Yes, I've had the chance to target an opponent's creature (in that case, a meddling mage from a fish player) intending to name Stp. But he countered it, which was just as well since I netted a counter. I could imagine other nasty stuff, from opponent's Welder's to fatties and I can see how that can be a really fun exercise.
7. Decree of Pain - I tested this thoroughly the night before the tourney as a replacement of 1 EE. Apparently, the mix of Orchards, fetches, underground seas and artifact mana was more than enough to make cycling this card viable on turn 3, so much so, in fact, that I had no qualms replacing 1 EE. Having said that, the strength of this card is really against fish and particularly so against versions running man-lands. The tempo loss from cycling this on turn 5, for example, against attacking Factories or Conclaves is practically GG. This and EE, as I mentioned, may be replaced by Rebuild or Hurkyl's at the drop of a hat. This is a control slot, same as Echoing T. or Chain of Vapor and may be adjusted, even replaced, by a duress-effect against control matchups. It's important to note that any change in these slots
does not essentially alter the deck flow. The structure is fundamentally resilient.
Matchups1. Grim Long - Yep, my bad. I was wishing I had 3 COTVs to deal with this. Maindecking this runs counter to the design however and would be a mistake. 3 in the side board is good. For that, I would cut Blazing Archon, Massacre and 1 Pithing Needle. Why am I holding on to the 2 SSS? Quite frankly, it's won me many games that would otherwise have been difficult, but that's ascribed to my Stp meta. If you're expecting something else, go ahead and cut.
2. Slaver - I wanted to test this out but didn't have the chance anytime before and during the tournament. I would speculate however that, all things being equal, Oath has a greater chance of going active before welder does, especially with the draw package outlined. Also, you have 2 maindecked solutions in the form of EE and Decree of Pain to deal with Welders.
3. Workshops - I am reasonably comfortable in any Workshop matchup, as an active Oath is practically GG and your draw package gives you that edge. Rebuilds should give you an out for COTV@2. Oxidizes are another if you're expecting a heavy workshop meta.
Let's hear those ideas and I'll post mine as they come along.
I will post a link to the tournament details when it's available.
