Looks like the Bloom deck couldn't quite beat it's worst possible matchup after being gifted a win in the semis. Can't say I'm too surprised about the outcome - Modern is a matchup format, and seedings/matchups in the top 8 were pretty much the most important factor in who won.
Regarding Twin: the problem with banning it is that it doesn't meet any of the criteria for a ban. It doesn't win too fast. It doesn't win too much. You can argue that it hurts diversity, but there are still plenty of Jeskai Control and UR Faeries decks that are viable without having to play Twin. Twin decks are playing sub-par creatures in order to combo - it's really not just as simple as "jam 4 Twin into a stock UR tempo deck to win more."
Is Twin shutting down other strategies? Of course! So are Thoughtseize decks, Cranial Plating decks, Lava Spike decks, etc. Just because there's a deck out there that's powerful, consistent, and has a swath of good matchups doesn't mean you must ban it - unless it demonstrates an oppressive leve of dominance repeatedly (e.g. pre-ban Jund).