I agree, bane is a great skill. I don't use it much in Castrum unless the adds are close together, otherwise I'd just waste it. SMN's are great for a lot of things, but their weakpoint is taking down tons of tons of adds, because we have no high damage AoE or even a low damage AoE that can target 1 enemy and when used, hits everything around that target.
I still love my SMN, and I am going to continue enjoying him.
EDIT: I take that back, we have the Egi Level 50 skill, but 300 second cd is.... Puke worthy.