To me, the rumble is most fun kind of pub fight. A barney is too personal, a brawl too sloppy, a fracas too hoity-toity, and a plain old fight is the kind of thing that'll get someone killed. No, give me the spectacle of a rumble in a pub, bar, or wine lodge and I'm happy. Blizzard beg to differ.
Blizzard say in the announcement:
"Each week, a different Tavern Brawl will pit you head to head versus another player using exciting and unique rules. One week might feature preset decks, while another week could have you crafting a brand new Tavern Brawl deck following specific guidelines, while others might offer buffs to specific minion types—who knows!"
Sounds pretty interesting, that. Changing up the rules can let your mastery and knowledge really shine through, testing how well you know the game and can adapt to the unfamiliar. Or I suppose you can wait for someone on the Internet to figure it out then copy their decks.
The mode is due to kick off in "mid-June", and the first several brawls will offer a free card pack when you win your first game in 'em. You'll need to hit level 20 to join in the Brawl at all, mind - can't risk having kids around for shenanigans like that.