Well that was fast. It's only been two months since Oko, Thief of Crowns was banned. It's pretty rare for Wizards to issue Modern bans in consecutive announcements, except for during emergencies like Hogaak, Arisen Necropolis's reign of terror. So I wasn't actually expecting anything to happen in Modern. However, last Thursday, that changed; I learned that the guy who always finished decks right before they get banned had just finished Simic Urza with a full set of Once Upon a Time, all but guaranteeing that something would be axed this time around..
When Wizards announced the coming announcement, everyone assumed it was for Pioneer. It turned out to be everyone but Pioneer. I'm guessing that not being instant-speed makes Inverter of Truth combo weaker enough than Splinter Twin to be acceptable there. Of course, an unfortunate result may be Modern's Twin die-hards upping the voracity of their calls for unbanning the enchantment.
As of today, Once Upon a Time is banned in Modern. One could look at this outcome as an inevitability, since Once had already been axed in Standard and Pioneer. While I considered this fact when making my watchlist a few months back, it wasn't my primary concern. I thought that Once would boost high-variance decks enough to become a problem. Those decks already didn't mind playing high-ceiling, high-floor games, and Once is very much a high-ceiling, high-floor card. The odds of opening with Once are only ~40%, and when that happens, Once is an amazing cantrip. When that doesn't happen, it's not a Modern-playable effect. I only thought it would appeal to decks that were already high variance.
I did call that Once would be banned, so that's two down with one to go for this year's watchlist. However, what I failed to predict was that Once would gradually be adopted everywhere. Back in December, Once was really only replacing Ancient Stirrings in Amulet Titan, and had made some moves in Infect. Since then, Simic decks have gained ample traction, and Once has come to permeate the metagame. Ubiquity isn't enough to get a card banned (see also: Opt; Thoughtseize; Lightning Bolt), but being free is, so Wizards has decided to pull the trigger before the Modern GPs get going.
Wizards was fairly brief with their reasoning this time, penning barely a paragraph of explanation. The passage still proves illuminating, especially its mid-section:
The consistency provided by Once Upon a Time allows these decks to much more reliably enact their early-game plan compared to other archetypes in the metagame, leading to less divergent gameplay paths.
Wizards is clearly aware of the effects cantrips have on game homogenization, or the reason they banned Preordain and Ponder in Modern. However, I don't think that they've ever spelled out the reasoning quite so clearly before. Wizards isn't worried about how the overall game is playing out; it's the early turns that matter: "leading to less divergent gameplay paths." Wizards apparently doesn't mind games playing out similarly, so long as they feature convergences during gameplay. But all that same-ness so early was too much.
Casting Once reduced the variety of opening turns to the point that games were looking too similar to each other. Again, Wizards has mentioned this as a reason to ban Preordain and Ponder, but those hits also came about due to other problems relating to Storm decks. All Once did was reduce variance, which apparently made games unacceptably stale.
As usual, Wizards cites data that we're unable to see. My data indicated that Once decks, particularly Amulet Titan, were very popular, but they weren't really performing that well; Amulet consistently put high numbers into Day 2 of SCG events, but such showings never translated to event wins or even top-heavy result distributions. Golgari Yawgmoth had some good results too, but nothing to indicate it was anything special (Except for it winning in Modern with Young Wolf). However, Wizards saw something different.
Over the past months, Once Upon a Time has become one of the most played cards in Modern, contributing to several of the most popular and highest winning decks.
The online meta data, which only Wizards has, must show that Amulet is both very popular and wins out of proportion to that popularity. I can only verify Amulet's popularity because again, my data shows the opposite as true. It is possible that Wizards is looking at the results across the board, but the deck data that I have access to doesn't back up that narrative. Simic decks were doing well, but not all of them ran Once. The overall League data must have been troubling.
Was Now the Time?
That being said, I do approve of this ban. Wizards has always known they got the card wrong, it's nice to see them acknowledging that fact. The data doesn't explicitly call for banning Once right now, but there are strong indicators that it was eventually going to be necessary. While you can reach that conclusion going through the hard data and watching Once's ubiquity tick up (34% on MTGGoldfish as of today, and 33% on MTGTop8), I think this deck is far clearer evidence:
When an otherwise entirely colorless deck like Eldrazi Tron is splashing a single Forest so it can actually pay for Once Upon a Time, the card's benefits are made plain compared to its opportunity cost. In my preview article, I was skeptical of Once since that the upside (of a free cantrip) was pretty low-odds. Seek the Wilds has almost the same effect as a cast Once, and it wasn't playable.
Apparently, Seek was closer to playable than I knew, because all it's taken is a low-odds upside for Once to trend towards universal, and then get banned. Consistency is powerful, and getting a boost for free, sometimes, is fantastic on a card that's already almost good enough.
Impact of the Ban
Without Once, the consistency of land- and creature-based green decks will fall. I'm specifically looking at Collected Company and Primeval Titan decks, but the principle applies across the board. The next-best green cantrip is Ancient Stirrings, and it's not as universally useful as Once (although the card should now recover from its slump). The decks that were running Once but never ran Stirrings could run Seek the Wilds instead, but that seems unlikely; if they weren't doing so before, I can't imagine they'd do so now. Always costing two mana and seeing one fewer card are significant power reductions.
The overall impact on the metagame is hard to say. Once was a widely played spell, but it wasn't necessarily a lynchpin card. The overall composition of the metagame is unlikely to change. However, the specifics of that metagame almost certainly will. Decks may not have needed Once in the strictest sense, but they were relying on it to be what they were.
Before Once, Titan decks were built around the Tolaria West/Summoner's Pact engine. Post-Once, they were more heavily creature-based. Tron decks, too, were more about non-creatures last year; recently, they've adopted Once in addition to Stirrings and subsequently play more creatures. Then there's the notion of Once reducing how many lands should be played in a deck to ensure competent openers. So while no decks should be outright killed by the ban, some major retoolings will be in order.
I would expect the metagame to continue its general trajectory. I don't expect any decks to be outright killed, and Once hasn't been around long enough to leave a gaping hole in its wake. The trend towards midrange decks evident in recent results should continue.
For that reason, I predict that Jund and Ux Stoneblade will be the big winners of this banning. How big that win shall be is a different question. They're not directly affected by the ban, and have actually won events. Meanwhile, their ostensible big-mana predators did run Once, so will be somewhat nerfed, and haven't been winning events. Amulet stands at a crossroads, while Tron should recover nicely; it had access to tons of cantrips already, and had just shaved some numbers to run Once.
This trend towards midrange may facilitate a trend towards more traditional combo, too. Rock decks tend to stave off Humans and similar combo killers via removal and card advantage. However, they tend to struggle against combo, since most of their answers are proactive and board-based while their clock is slower compared with aggro. Combo then has time to claw back into the game after eating a string of Thoughtseizes. I've already heard some murmuring about Ad Nauseam's return, and it's worth remembering that Veil of Summer, another high-power cantrip of recent times, is still legal.
Which brings us to the fate of Amulet Titan. It would be one-dimensional to dismiss the ban's impact and say that Titan will just return to Stirrings. Adopting Once allowed Titan to build in a very different direction from previous incarnations, and the new decks cannot easily switch over. Consider this list from last year:
...compared to this more contemporary list:
Dryad of the Ilysian Grove turned Amulet from a land combo deck into a land toolbox deck. Losing the bouncelands made space for more utility lands, and Dryad lets Valakut kill much easier than Slayer's Stronghold and Sunhome, Fortress of the Legion. Once Upon a Time dug for Dryad, which had become the lynchpin of new Titan decks, making this new strategy faster and more consistent than the older version.
Stirrings is no replacement for Once. The latter finds creatures and lands, while Stirrings only finds lands and Amulet of Vigor. The one way Stirrings can help make the combo happen is by finding Tolaria West, which finds Summoner's Pact, when then finds the needed Dryad or Primeval Titan. To continue entirely unchanged, these decks will have to replace Once with Seek the Wilds, which again is far worse.
If Seek isn't good enough, then I'm not certain what kind of lot Amulet will make out with. It could easily revert to its classical style, but I don't think it wants to. The land-value/Valakut plan is far harder to pull off with the older version, but is likely more powerful on its own merits, as evinced by the archetype's gradual transition. Amulet Titan has been part of Modern since 2015, but it's always been pretty niche. The barrier to entry was fairly high, since the tutoring lines made going off complicated. The enthusiasts will be fine, but I don't know if the players that have come to Amulet Titan recently will be willing to put in the time to learn the more complicated deck and keep its metagame presence high.
Keep Moving Forward
Overall, I think that banning Once Upon a Time sooner rather than later was a good decision. It may have been fine at the moment, but there were signs that it would eventually have taken over to a dangerous degree. Modern will chug on largely intact, though the question of how to replace Once will redefine decks. It also means that the Regionals data is for a dead format, so I'll have to start over with the data collection.