MapleThey provide more utility than any other class in the raid through
Stampeding Roar,
Rebirth,
Innervate, and most importantly for this fight their exceptional off-healing capabilities. Tie that all together with them being virtually invincible when not inside
Ravenous Frenzy and tanking every mechanic to their deaths :) (: Boomkins are unique in that they are extremely sick and extremely cringe at the same time.
LozyNot only do you have to run a 5k for Phase 2, but we knew Veils were going up in size in Mythic. Combine this with
Starfall for Domination Arrows in Phase 1, good single target damage (especially for add sets in Phase 2 to skip orbs, etc) and being a very tanky class, and you get it.
We've been publicly calling them the best class in the game for awhile, so we went in with plenty of options along with 3 people maining it. The switch to 4 happened later from a Shadow Priest since and we put a geared rogue in that slot.