In any spoiler season, there comes a point where the flagship cards are all spoiled, and it's time to fill out the rest. Previews for Phyrexia: All Will Be One are approaching that point, but there's still time for something shocking to emerge.
That's not to say that nothing interesting is being spoiled. The last week or so of spoilers is when the solid, but not overly powerful, cards come out. There's nothing necessarily format-shaking this week, but rather a few cards that could do a lot of work in the right deck. If the right deck or metagame exists, anyway.
The Proliferation of Proliferate
While I wouldn't call myself a fan, I do make a point of keeping up with Mark Rosewater's content. As the most prolific member of Wizards in terms of engaging with the community, he is our main source of insight into Wizards' mind and game direction. Most of content being reading the tea leaves of Magic, any inside source is welcome. Which is a long-winded way of saying that One feels, mechanically, like the most MaRo set imaginable.
What I've learned from Mark's writing is that he likes counters. He likes counters of any type and he likes manipulating them. Doubling Season is one of his favorite cards, and proliferate one of his favorite mechanics. I've always had the impression that he's disappointed/miffed that neither has been relevant in constructed, and he's constantly iterated on their mechanics trying to find a way to make them matter. It's looking like he has finally succeeded.
Counters and proliferate are the central mechanics of One and to boost their power, a lot of cards have proliferate incidentally. Thus, for the first time that the limits of my Google-fu could find, proliferate may show up in serious Standard decks, and maybe even Pioneer. That is a big maybe, though.
Expanding for Value
In terms of just gaining value from proliferating counters, the value will be +1/+1 counters and planeswalker loyalty. The poster child for the incidental proliferate cards works well with the latter, but not the former. Experimental Augery is strictly better than Anticipate because it does the same thing plus a cookie. As Anticipate has seen play in both Standard and Pioneer in the past, Augury is certain to see play as well.
The key phrase being "in the past." Anticipate saw Pioneer play up until Impulse was reprinted last year, rendering it obsolete. As Impulse will be legal for most of Augury's Standard life, I can't imagine that Augury will see play in the near future. For Augury specifically to see play requires that a deck is okay with seeing fewer cards in exchange for getting more counters onto permanents. As all the decks that currently play Impulse are combo or tempo decks without planeswalkers or a counter strategy, it looks like a totally new deck is necessary. Even then, an extra couple counters may still prove worse than looking at more cards.
Expanding to Win
One option is to use proliferate as the means to finish off opponents with poison counters. Remember, Venerated Rotpriest is potentially broken, and once the opponent has even one poison counter, proliferate becomes a clock. Modern Infect would not play any of the (currently-) spoiled proliferate cards. However, a Pioneer or Standard deck likely would.
The best combo with Rotpriest (again, currently spoiled) is technically not proliferate, but it does serve the same purpose. Infectious Bite can clear the way for a toxic creature to attack, and with Rotpriest generates two poison counters, one of which is guaranteed even if Bite is countered. That sounds really great for Standard. It's far from being Modern viable, and I'm not sure such a deck would work in Pioneer given Mono-Green Devotion, Rakdos Midrange, and Humans, but Rotpriest plus the proliferate cards seems like a good place to start.
The problem with this all is that outside of proliferating poison counters, Standard and Pioneer poison will always be slower than just killing with damage. Toxic is much worse than infect. Rotpriest offers combo potential, but that will be best unlocked in Modern or maybe Legacy.
I can say with certainty that someone is going to try to make Poison work in both Standard and Pioneer. However, unless they're going for a combo kill with Rotpriest, I'm skeptical that it will be fast enough to compete. In Modern, there are so many better ways to kill with poison that I don't think proliferate has a chance. That said, there will always be those willing to try the weird options.
There's Always One
I'd be remiss at this point not to emphasize how nicely proliferate works with planeswalkers. Yes, I know I did already mention it above, but Wizards really wants to make sure that players are aware of the interaction. Apparently, someone there desperately wants Superfriends to be good, because they printed this card:
The idea here is to use the Gauntlet to rapidly amass counters on the tons of planeswalkers a Superfriends deck plays, play more to get more counters as they'll all grow each other with each 0 activation, and then win by taking all of the turns. Which sounds really powerful (and honestly quite fun). The problem is that Superfriends decks have historically not worked because they're really slow and clunky. Once the deck gets going, it's utterly overwhelming, but getting to that point usually takes far too long.
There's nothing in One that will stop Superfriends from being so top-heavy. However, all the incidental proliferate cards will help it get going and rapidly build towards its endgame. This will likely produce viable decks in Standard, while older formats will remain too fast. That said, I do expect to lose to Modern Superfriends in the next year. Not because the deck will actually be good, but because that's how my life works.
Lots of Answers
Whoever was pushing Ichormoon Gauntlet might have been too vocal about the deck, if all the answers to planeswalkers are an indication. I don't know if the number of removal spells for planeswalkers is actually higher in One than other sets (though it would be thematically appropriate), but they all are more aggressively costed than usual. At time of writing, there are three two-mana removal spells (two white, one black) and one at three-mana. Two of the two-mana spells will almost certainly see widespread play, and I'm intrigued by the three-mana one as well.
Ossification is at the top of my list for the simple reason that I'm definitely going to play it. Chained to the Rocks has seen at least some play in every non-Vintage format, and is currently a staple in Pioneer Fires of Invention decks. Ossification costs more, but hits planeswalkers too. It also isn't as restrictive about land type, though needing basic lands likely means that Fires won't be switching.
Instead, I will personally be switching out Ossification for my sideboard Portable Holes in Pioneer Humans. One versus two mana is a burden, but that is more than made up for by having more targets. Frequently in the Rakdos and Mono-Green matchups, I've boarded in Hole and wished I could throw something three or more mana into it. Being able to remove Kiora, Behemoth Beckoner or Karn, the Great Creator is incredibly potent, especially since it saves me the trouble of attacking them. Cleanly removing Old-Growth Troll and Graveyard Trespasser // Graveyard Glutton is nothing to sneeze at, either.
It's been some time since Diabolic Edict et al. were constructed staples. The problem is that Edicts always trade for the worst target, outside of something like Crackling Doom. The only exception is in Legacy where Sudden Edict sees play, mostly for killing win conditions in grindy control matchups to get around counters. Sheoldred's Edict might be an exception thanks to its versatility.
The use that immediately jumped to mind was against Dark Depths in Legacy. Sudden Edict isn't really for that matchup, as there are usually other creatures to sacrifice rather than the Marit Lage token. Sheoldred's might get around that, as not every Depths deck also runs Urza's Saga, meaning that "sacrifice a creature token" really means "sacrifice Marit Lage." There's also the general utility of choosing planeswalkers, which might be enough for Modern play. Unholy Heat makes that less likely, though not impossible.
Vanish into Eternity
White has a lot of ways to answer nonland permanents these days. Every format has Leyline Binding, while Modern and beyond have Prismatic Ending. This suggests that there isn't much room left for these effects. Certainly not ones that can't be cast for one mana. On an intellectual level, I understand this, but I can't shake the feeling that Vanish into Eternity is Modern-playable.
Not hitting creatures efficiently is a huge ding against Vanish. However, it hits everything else. And gets rid of it for good, to boot. There have been numerous times I've wished that Fate Forgotten was playable against decks that recur artifacts or play Welding Jar, especially against Ensnaring Bridge and Chalice of the Void. That Vanish also vanishes Leyline Binding and Teferi, Hero of Dominaria for three mana is no small thing.
The use I'm thinking: in a metagame where prison and control are prevalent, Vanish becomes a very powerful removal spell. Able to deal with all problematic permanents permanently, it serves as a strong counter-boarding option. This wouldn't fly in the metagame Modern currently has, but if enchantments and artifacts receive more widespread maindeck play, this could start to creep in as a utility weapon. I'll definitely be keeping Vanish in mind when building sideboards in the future.
A Minor Callback
The final card today is one that has a very obvious home, and another that players are too hopeful for. Mental Misstep is a very messed-up card, though many today don't realize why. Being able to answer any one-drop for two life is incredibly strong, and the fact that Misstep answers itself ensured that during the (brief) time it was legal, every deck had to play Misstep just to counter Misstep. (The blue decks benefitted most, though, since they could also hard-cast the card.) Wizards has decided to print a fixed and tweaked version, and speculation is running rampant.
Memories of Mental are certainly coloring evaluations of Minor Misstep. However, the bigger issue is that players see that there are lots of powerful one-mana spells being played in Modern and think that automatically makes this spell Modern-viable.
Bad Timing, Wrong Answer
In order for a counterspell to be playable, it needs to be both timely and efficient. Counters are great if and only if they are in hand and castable when the spell they need to counter is on the stack. General counters like Counterspell perform well because they are never fully dead, while Flusterstorm and similar narrow counters are confined to the sideboard.
Minor's problem is that while it is great on the play to counter an opponent's turn 1, it does nothing on the draw. Countering a turn one Ragavan, Nimble Pilferer is good. Staring down your Misstep while your opponent on the play deploys Ragavan is horrible. In later turns, the value of one-drops, and thus the value of Misstep, drops considerably. This relegates Misstep to a very niche role.
A Legacy Weapon
Where that won't be a problem is Legacy. Countering Ponder on turn five is at least as relevant as countering it one turn one. Arguably moreso in certain grindy matchups. This is also a format where Pyroblast is a frequent sideboard card, meaning that Misstep's targets are much stronger and remain relevant over a longer timeframe. Also, at minimum, in matchups without many one-drops, it can be pitched to Force of Will. I expect Delver decks at minimum to start incorporating a few Missteps very soon.
There was nothing truly format-shaking spoiled over the past week, in my book. However, there are a lot of cards that could subtly move the needle for many decks. It doesn't take much of that to set off a chain reaction that can lead to format shakeups. One looks like a very powerful set overall, and while I think the big splashy mythics and rares will get the press (and will keep an eye on Rotpriest), I think that it's the uncommons and commons that will have a lasting impact.