I'm fully expecting there to be a huge wave of "AMG THIS IS IMPOSSIBLE!!!ONE!!11" the first few months after Cata launches. It was the same with Wrath. Then people gear up properly and then blow through instances.

I haven't seen any fight so far in Cata where I said "Man, that's just not boxable." I mean come on people. Multiple people have boxed 10m ICC up to Lich King and one or two people have actually 4-boxed Lich King. That's insane. If ICC is boxable then without a doubt any and all Heroics in Cata will be doable.

If nothing else, we boxers are quite creative when it comes to problem solving in game.