UK @ 68 is pretty freakin leet.

My Pally & Shaman crew managed at 70....JUST.

The way I handled the first boss, especially with the shammies, was to keep them on follow, right on the tanks butt.
That way it makes sure that Ice tomb and the summoned adds, all cop damage from aoe's like consecrate or chain Lightning.
Generally, the damage taken from Ice tomb is almost negligible. If I was unlucky, and the tank copped it, I would just have the shaman nuke it.

Which, to be honest, is my method with that boss. Nuke Nuke.

My lock crew on the other hand really, really struggled on this boss.

I actually farmed that boss for a whole level to get the spell blades on each of the shams...71-72. From the door to the first boss is the most XP beneficial area of the instance and I could clear it in 15-17 minutes. Was a fast way to burn a level that I really was struggling for motivation for. That spell blade has a terribly low drop rate.