Zvi says ban it, and the pros I’ve seen talking about it lean towards the ban camp, but there are dissenters like BenS. People also almost universally like it in limited. Are they right? Are they highly confused? What’s really going on?
From the baseline of the Paris mulligan (draw 6, draw 5, etc), on a 6-card keep, the Vancouver mulligan adds scry 1 and the London mulligan adds Loot 1 (discard to bottom of library). London is clearly better, but plenty of times you’ll scry an extra land away like you would have with a loot, or the top card will be the one you would loot away anyway and there’s no real difference. Other times you’re stuck with a clearly worse card in hand. It’s better on 6-card keeps, but it’s not OMFG better.
Except that’s not quite the actual procedure.. on the London, you (effectively) loot, THEN you decide whether or not to keep. That lets you make much better decisions, seeing all 7 cards instead of just 6 before deciding, and the difference on a 5-card keep is that Vancouver still just adds scry 1, but London adds Loot 2. That’ adds up to a HUGE difference in starting hand quality. And you can still go to 4 if your top 7 cards are total ass again. I’d argue that the London is fine at 6 but goes totally bonkers at 5 and lower.
If you have decks that rely on card quantity more than a couple of specific quality cards, going to 5 cards, even best-5-out-of-7, is still a big punishment. That’s most limited decks, where a 90th percentile 5 is going to play out like a 40th percentile 7, or something like that depending on archetype. Barring something absurd like Pack Rat, aggressive mulligans aren’t a strategy. You mulligan dysfunctional hands, not to find great hands. London just lets you be a bit more liberal with the “dysfunctional” label in limited, and it’s generally fine there.
For Eternal formats, where lots of decks are trying to do something powerful and plan B is go to the next game, London rewarded all-in-on-plan-A strategies like Tron, Amulet, and now Whirza (which also just got a decent Plan B-roko). Before rotation, and for most of 2019, it looks to me like Standard was a lot closer to Limited, at least game 1 in the dark. Aggro decks really don’t want to go to 5 (although they’re better at it than the rest of these). Esper really doesn’t want to go to 5. Scapeshift really doesn’t want to go to 5. Jeskai really doesn’t want to go to 5. Not that they won’t if their hands are garbage, but their hand quality is far more smoothly distributed compared to a Tron deck’s highly polarized Tron-or-not, nuts-or-garbage and that means keeping more OK hands because the odds of beating it (or beating it by a lot) with fewer cards isn’t as high. Aggro decks need a density of cheap beaters and usually its other flavor (pump in white, burn in red, Obsession/counters in blue, etc). Midrange needs lands and 4-5 drops and something to do before that. Control needs enough answers.
There just aren’t that many good 5-card combinations that cover the bases, even looking at 5-out-of-7, you’re quite reliant on the top of the deck to keep delivering whatever you’re light on. There wasn’t any way for most of the decks to get powerful nut draws on 5 with any real consistency, even with London, so they couldn’t abuse the 5-card hand advantage because going to 5 really sucked. Then came Eldraine.. Guess who doesn’t need a 7-card hand to do busted work?
Innkeeper doesn’t get to 5 that often, but any 5 or 6 with him is better than basically any 6 or 7 without, so the idea still applies. Hands with these starts are MUCH stronger than hands without, and because of London and OUaT, they can be found with much more regularity. If you take something like Torbran in mono-R on a 5-carder, WTF are you keeping that doesn’t have to draw near-perfectly to make T4 good? Same with Embercleave in non-adventure Gruul, you can only keep pieces and hope to draw perfectly.
Oko not only has a self-contained nut draw on 5 cards, its backup of T3 Nissa is a hell of a lot easier to assemble on 5 than, say, a useful Torbran or Embercleave hand or a useful Fires or Reclamation hand. Furthermore, thanks to OUaT (and Veil for indirectly keeping G1 interaction in check), it can actually assemble and play a great hand on 5 far too often. Innkeeper can also start going off from a wide range of hands. The ability to go bananas on a reasonable number of 5-card London hands certainly stretches things compared to where they were with Vancouver.
Maybe that will make for playable (albeit different) Eternal formats with a wide variety of decks trying to nut draw each other, kind of like Modern 1-2 years ago before Faithless Looting really broke out, with enough variance in the pairings lottery and sideboard cards that tier 2 and 3 decks can still put up regular results. I have my doubts though- Modern was already collapsing away from that, and reducing the fail rates of the most powerful decks certainly doesn’t seem likely to foster diversity from where I sit- and if there is a direct gain, it’ll be something degenerate that’s now consistent enough to play. Yippee.
It’s possible that some Standards will be okay, but even besides the obvious mistakes in Oko and Veil, this one has some issues. You can’t ever have a cheap build-around unless it’s trivially dealt with by most of the meta (Innkeeper could be if Shock, Disfigure, Glass Casket, etc were big in the meta), in which case why even bother printing it? You can’t have functionally more than 4x 1-cost acceleration without polarizing draws to 3-drop-on-turn-2 (or 5+ drop on turn 3) or garbage. With only one card, and especially one card that might actually die, you can’t deckbuild all-in on it or mulligan to it. With the 8x + OuAT available now, you can and likely should if you’re in that acceleration market at all.
I don’t trust Wizards to not print broken cheap stuff, and they probably don’t even trust themselves at this point, assuming it’s not actually on purpose, which it likely kind of is. I barely mentioned postboard games where draws are naturally more polarized (and that polarization is known during mulligans), which leads to more mulligan death spiral games. Nobody’s freaking out when a draft deck keeps 7 because it keeps plenty of average-ish hands as well as the good ones- you just have to mulligan slightly more aggressively. When Tron or Oko keeps 7, you know damn well you’re in for something busted because they would have shipped all their mediocre hands and you have to mulligan to a hand that can play.. until we get a deck that can actually bluff keep a reasonable-but-not-broken plan B/C sometimes to get free equity off scared mulligans/fearless non-mulligans.
I wish I had a clean answer, but I don’t. If all I were worried about were ladder-type things, I’d say you just get one mulligan, and have it be a London plus a scry, or even look at 8 and bottom 2, and you’re stuck with it. If your hand is nonfunctional, then you just lose super-fast and go to the next game or match, no big deal. That’s a lot of feels bad on a tournament schedule though where you lost and didn’t even get the illusion of playing a game and you’re doing nothing but moping for the next 30-40 minutes, and a lot of people aren’t even playing Magic in the way pros and grinders do.
To use a slightly crude analogy, they approach Magic like two guys who are too fat to reach their own cocks and agree to lay side-by-side and jerk each other off. Some like to show off, a few like to watch, but it’s mainly about experiencing their dick, er, deck, doing what it’s built to do, and they can’t just play with themselves. For those people, the London mulligan is like free Viagra making sure their deck is always ready to perform, so they absolutely love it, and that player type is approximately infinity times more common than the hardcore spikes who can enjoy a good struggle with a semi…functional hand.
For those reasons, I think we’re stuck with it, for better or for worse, and the best we can hope for is that WotC is cognizant of not allowing anything in Standard to do broken things on 5 with any frequency and banning ASAP when something gets through.