He'll have mage sheep as well, so it should be very doable when he gets to the humanoids. The elementals will be tougher, but between Bind Elemental and Entangling Roots he should be OK.

Another one that is pretty easy is Blackrock Caverns. For boss 1, be sure and use your mage's AOE freeze right before you run from the Chains and you'll be golden. Skip boss 2, 3 is skipable if you can't time dragging him through the floor beam, and the last boss drops a fabulous caster trinket if you can slow or freeze the adds enough times to get them off your tank and heal him up a few times during the fight (mage AOE freeze is helpful here too). Good luck!