Did VoN3 but Marut was being kited so I didn't get hit too much. I did get a little aggro but difficult to see in the heat of the moment if I was getting hit by grazing/glancing/regular hits. I've got a feeling you'd need 70+ AC for him.
51 AC in elite shadow crypt worked fine up until the boss fight with Nereza. Wasn't getting missed all the time as wraiths and what have you have massive high AB but it was often enough that with a little bit of movement I didn't have to heal while fighting but rather could just heal at the end.
Trolls in Gateway to Khyber need about the 53 AC sustainable that I can manage but with that I didn't get hit at all (until someone gave me red alert and I ended up fighting about 20 trolls that ended in a run back from Korthos).