Hunters are, however, the best class for tranqing shamblings while maintaining their DPS. Rogues will lose a lot by switching, hunters simply have to be ready to tranq, and then lose a GCD.
Phase two, you will probably be misdirecting ragings to the tanks, and then DPSing them. Mages are good for taking down orbs.
Phase three, you'll want to clear any ragings still up, then stack with the rest of the raid for valkyrs. You can safely stand at enough range to be able to continue DPSing the Lich King.
Phase "four", ragings again.
Phase five, stay at range for defiles and multi-shot vile spirits and single target them. You want to have a mouseover distracting shot, if possible, so that you can pull them towards you and away from the raid.
Phase six, I never bother DPSing. Waste of ammo