Okay, wild ride might be overstating it, but it's interesting just how much variation there is between the power levels in Standard and Block Constructed. The intriguing part is that the door swings both ways. You might think that a card being good in Standard would mean it was automatically among the best cards in the junior leagues of Block Constructed, but it turns out that context matters a great deal. So some of the best cards in Standard are actually close to unplayable in Block, and vice versa.
So to get an idea of what distanced Standard from Block, we polled a bunch of pros and slimmed down their picks to the five cards that got worse in Block versus Standard, and five that got much, much better.
This can't be right, can it? This card sees play in Legacy. Heck, this card sees play in Vintage. How in the world could it possibly be bad in Block?
Well, the short answer is that it's not bad. The longer answer is that it's not nearly as good as it is in Standard. I'll let Patrick Chapin explain.
"It's not that Thoughtseize is bad, it's that it has a different use in Block. There isn't a Sphinx's Revelation, so it's not like you're taking the one card in my deck that can do that one thing. There's a lot more redundancy in Block," he said.
That's not to say Thoughtseize isn't seeing play. It certainly is. It's just a different kind of card, one that's less of a dominant hammer and more of a single tool in an entire arsenal. In other words, it's good—but it's not great.
Speaking of good but not great, Thoughtseize's PIC (that would be Partner In Crime) Gray Merchant jumps off a precipitous power cliff when it comes to Block Constructed. It's not the Merchant doesn't get played, as he certainly does, it's just that the type of Mono Black deck that's good in Block doesn't much lend itself to a five mana 2/4, even if it does come with a Drain Life attached. That deck wants to be attacking with under-costed beaters, not trying to build up a board presence to hopefully drain for a few and recoup some life on a life total that it really could care less about.
Darlings of Pro Tour Theros Thassa, God of the Sea and Master of Waves just can't muster up quite enough devotion to make them worth playing in Block. The cards themselves are powerful, the problem is that they lack the support needed to actually turn them on. As Paulo Vitor Damo da Rosa put it: "You end up having to play cards like Mindreaver, and that's not where you want to be."
There's a risk inherent in Banishing Light. A risk that what you put away won't stay gone. A risk that, at precisely the wrong moment, the light will go out and the banishment will end. A risk that you'll just plain get blown out by something as simple as Unravel the Æther.
"Everyone has enchantment removal here," Conley Woods said.
The problem with Dissolve is one that we're going to see as a boon for many of the next cards on our list. You see, control in Standard is a tyranny ruled by twin overlords Sphinx's Revelation and Supreme Verdict. Remove those two from the equation and control starts to look very, very different. One way it looks different is that it can't count on Supreme Verdict to clean up the mess left by slow mana and three-mana counterspells. Without Dissolves parents to keep things rolling, Dissolve is a much less enticing prospect, even for blue mages.
Prognostic Sphinx, the all-scrying one, might just be the breakout card of this Pro Tour. Armed with several attributes that make it attractive in Block Constructed. It flies over Elspeth tokens, it's low enough power to live through Elsepth's wrath, kills Elspeth in two hits, and is resistant to removal. Prognostic Sphinx is another in a line of cards that benefits from Supreme Verdict not being around to make it look silly. Damo da Rosa called it the best finisher in the format, and the legions of Sphinxes lined up staring each other down pretty much confirms that notion.
Of course, if a bunch of 3/5s and 2/4s are going to repeatedly crash into one another for no effect, a cheap Pplaneswalker that can find and cast more 3/5s and 2/4s, all while serving as a win condition in its own way, certainly has a chance to shine. Brian Kibler, a man who knows his way around an aggressive deck, said that there are few ways to pressure planeswalkers, especially cheap ones. And since aggressive creatures typically don't have high power in this format, that means Ashiok's ability to go straight to five loyalty makes it awfully hard to run down.
Look, maybe someone will make Prophetic Flamespeaker work in Standard. The format is still young, and there's a lot of raw power there. But here, in the cozy confines of Block Constructed, there's less removal that just outright kills it without losing some value. Conley Woods called it the best red card in the format. Some would argue that the true power is Stormbreath Dragon, but the fact that there's even a conversation speaks to how much better regarded Prophetic Flamespeaker is in Block than Standard.
So I asked a bunch of people this question and Silence the Believers was easily the second-most given response, right after Prognostic Sphinx. A touch too expensive in Standard, Silence is actually one of the best cards in Block. Part of the reason is the general lack of unconditional removal, which Silence does well but expensively. Part of it is that Strive can shut up a whole host of rabble rousers. But the icing on the cake is that the enchanted clause, the one that's largely ignorable in Standard, is incredibly relevant on Theros.
"A lot more players are trying to make one big guy and attack," Damo da Rosa said. "Because of bestow, this card is very good."
Sylvan Caryatid is a very good card in Standard, but in Block, the plant stands alone for a number of reasons. For one, it's pretty much the only one of its kind around. Sure, Kiora's Followers and Voyaging Satyr are semi-reliable mana production, but they're barely able to be called fixers. Sylvan Caryatid, on the other hand, is a no-nonsense, five-color mana producer in a world with little reliable ramp on part with Standard. What's more, there's no Supreme Verdict to sweep it away with all of the friends it helps cast. Once you cast a Caryatid, it's planted firmly on the battlefield for as long as you'd like. Throw in being able to reliably block most everything on the ground in the black and red aggressive decks and you have a card that really shines as one of the best of the best
Honorable Mentions:Market Festival, Kiora, the Crashing Wave
Market Festival gets the nod because it's apparently playable (by No. 17 Josh McClain, No. 12 Alexander Hayne, and Sam Pardee, even) while it isn't remotely playable in Standard. Kiora, the Crashing Wave gets a nod too, and probably makes the list for all of the same reasons Ashiok does. It's a card advantage engine that shines in both control matchups and against the "one big monster" plan.