Me and Sinssito rushed 2,7k in a day or two as ww/hpala, and we still beat alot of good comps that you just mentioned, such as Warr/healer (Markzxy/Purpolz & Blaston/Aristippes/Goldinnka), Mage/Druid (Coldsiemensx & Chilezx), Ret/Hunter (Dartmeganz & Djfreezer). And i'm not a really "skilled" healer, so if me and Sinss could make it vs those "only playable teams", everyone can, if you're good enough to play at that mmr of course. (Also imo, hpala is one of the worst healers atm, after priest I guess)