Sub Rogues: You cannot get them off of you. Their control and pressure is unbelievable. They do crazy dmg on top of all that control as well. Total nightmare if played by someone with half a brain.
My fix would be to reduce their damage. You can't have that much control/pressure/self healing AND high dmg on top of it. Absolutely nuts.
Warriors: "i'm rooted, rooted, LOL got him he's dead"
Nerf the damage.
Deathknights: They don't let you move, they don't let you cast, they don't let you heal.
I can't even figure out how to balance them. Their damage isn't exactly high but you aren't allowed to do anything while they are on you.
Resto Shaman: They aren't exactly the hardest healers to kill, but wind shear is on too short of a cooldown. Coupled with certain classes they can completely shut down casters to a laughable level.
Windshock needs a real cooldown. Like 10 seconds or better.