So, I posted awhile ago regarding a spec specifically for main tanking the hard hitting Ulduar bosses which included improved demoralizing shout. Originally, I had posted about using this spec.
I'm finding that my threat while missing the arms talents is really lackluster. I frequently find my top warlock (doing 8k DPS or so) catching up to me. This didn't happen with the arms talents. As such, I'm considering dropping Shockwave and Damage Shield for single target boss tanking. Can I get some feedback on this spec?
A more survival-based spec. is going to have less threat, you can't really have it both ways. You're either going to be taking more damage and hence dying more often, or your Warlock friend is going to need to learn to back off again.
a) Vigilance the Warlock.
b) Intervene him if/when possible.
c) Make sure your Rogues are constantly TotT'ing you and Hunters are MD'ing. Threat should not be an issue if these two classes work together to keep you on top.