Yo, I que BGs a lot and arenas sometimes with either my rogue, hunter, or resto shammy and for me bg ques are 6-8 mins long and arenas around 1-2min long.
Healers don't die instantly. Mostly it is your teammates dying instantly in bgs.
Priest, druids, and monks are strongest imo. Blues and holy paladins are rare. Every one usually either goes ret, elemental, or enhance imo.
I've seen a couple premades in 2's, haven't seen any 3's.