Quote from FlyingDelver »The mirror is right now not relevant at all actually. This might surely change, but from the current point of view, a decay is very bad.
It's going to be more relevant once Assassin's Trophy releases, even if it's just for a few weeks. There was a ton of Jund everywhere when BBE was unbanned, people just like playing B/G/x. This forum consistently undervalues cards (Grim Flayer, Collective Brutality, and Lily the Last Hope as recent examples) because people look at cards in a vacuum.
Decay is a problem right now because there's a bunch of relevant stuff that it doesn't hit. That problem is alleviated once we have access to Assassin's Trophy, which will give us 3-4 maindeck answers to anything. When you have that many answers to anything, your narrower answers get the opportunity to line up better, and it's easier to work within Abrupt Decay's CMC restriction. I'm not saying any of this to advocate for playing Abrupt Decay in an Assassin's Trophy world (jury's still out on that), but within that context Vraska's -3 is more likely to find a target, provided you've sequenced your removal to maximize that chance. I think that having that effect as a repeatable option is also incredibly good, the same way that getting multiple uses out of LotV's -2 can snowball a game.
I think that you can actually bring Vraska in against any midrange or prison deck that plays a lot of permanents, I was using the B/G/x mirror as an example because I think we'll be playing a lot of them this fall.