Resto Druid, Guardian Druid, and Fury Warrior were the most annoying for me, because I hadn't played them the whole expansion.
Frost Mage, Fire Mage, Havoc, Ret Pally, Doomkin, Feral, Destro, Affliction were all pretty easy, if I didn't have the best 2 legends I usually always had the neck or sephuz, so they were pretty easy 910+