deck for KTK/BFZ
A couple card explanations:
Fathom Feeder
One of the strongest tools for control in the new set. A great defender early on that turns into a card draw engine in the late game. In a format where lands matter, we want to be tapped out at the end of the opponent's turn, and Fathom Feeder is a great resource.
Dragonlord Ojutai
If this guy sticks, the game is won. The reason there is only one in the mainboard is beause I imagine Languish will be quite rampant in the early stages of the BFZ standard, and we don't want to get blown out. There is one in the side in the case that we are playing against a deck that doesn't run Languish.
Dragonlord Silumgar
How I'll imagine this deck wins most of its games. The only card that would really blow this deck out with a Silumgar out is Crux of Fate.
Blighted Cataract
In the late game, where there is no Fathom Feeder to empty mana out to, or if it is time to draw 2 for 7 rather than draw 1 for 5, Blighted Cataract does its job well.
Shambling Vent
Getting mana screwed sucks, but doesn't suck as bad when a couple of the lands in question are Shambling Vents. A decent blocker and, in some scenarios, a great clock/racer, Shambling Vent lets us keep up pressure even without a hand. Also, great to activate when the opponent casts Foul-Tongue Invocation.
Ojutai's Command
This card + Fathom Feeder is the reason to play Esper in standard. There will be a very real amount of times where Ojutai's Command will read: "Kill target creature. Draw a card" and others where it will act as Cryptic Command. There are only two because having a Command without a Feeder in the yard only makes it half as powerful.
Halimar Tidecaller
With the ability to bring back a counterspell or a wrath, and a sometimes-relevant flying ability, this card has insane potential as blue's version of Den Protector. Again, there are only two because having one without an Awaken card in the yard is pretty bad.
Utter End
In a world where there is no Hero's Downfall, Utter End is a strong replacement at instant speed. Exile is important with Hangarback Walkers, Den Protectors and mirrors around. I imagine that Esper Dragons will be a popular deck in the season and it's good to prepare for the mirror. The reason that there are only two is because Awaken and Shambling Vent can be more relevant than anticipated, which Utter End cannot hit.
Virulent Plague(SB)
Hangarback Walker.
Some exclusions:
Ruinous Path
Ruinous Path feels horrible to play. An sorcery speed 3CMC removal spell is something that control really isn't looking to play with a couple of exceptions (Detention Sphere). The Awaken is even worse- no control deck considers a 7-mana ETB Hero's Downfall 4/4 a powerful play. Utter End is a mana more, but I'll gladly pay one more mana for instant-speed removal.
Jace, Vryn's Prodigy
Jace was a very powerful card in the last season. But with the loss of cards like Thoughtsieze and Hero's Downfall, and with cards like Languish weakened, and with the inclusion of cards like Fathom Feeder and Halimar Tidecaller, the targets for Jace are much less diverse and don't feel as powerful. Who knows, it's possible that Jace is just indeed the correct choice. This card is the one that I am the most conflicted about.
Hangarback Walker
Hangarback Walker is great. Great enough for a Dragons control deck? No. Against decks that do care about it, we're better off playing a Dragonlord in its place.
Treasure Cruise
Treause Cruise feels too clunky with 5 delve spells and a lot of recursion. There are rarely times where Treasure Cruise is more relevant than a Dig Through Time.
Gideon, Ally of Zendikar
Gideon is great, but not better than the Dragonlords. With a useless ultimate and a rarely useful +0, he is only a 4/4 "indestructible on your turn". That doesn't quite make it for this list.
Ob Nixilis Reignited
Ob Nixilis seems too slow to be powerful. The +1 is an extremely mundane ability for 5 mana. The real power in this card is its -3, but I imagine times will be rare where it can do so more than twice. Powerful, but Ojutai pressures our opponent and keeps our hand stocked up a little better.
Languish
We do have a Languish in the side, but it will be used sparingly. Without an effective Lightning Bolt, red is dead in the new standard and aggro strategies will become Abzan strategies, where Languish's power is diminished due to Siege Rhino. There is still one in the main for any B-list aggro fecks, Deathmist Raptor decks and Undergrowth Champion decks.
Stasis Snare
Statis Snare has the potential to be very powerful, almost to the point of being the new Hero's Downfall. However, in a format where Dromoka's Command is prevalent, expecting to rely on this card as a form of instant-speed removal will lead to many lost games, especially with impact creatures such as Siege Rhino running around.