I shatter pretty often. Basically, if my foe is about to die anyway, or if I have 3 illusions up and I can easily roll up another set of illusions (which is often easy because I bring at least two illusion skills in my optionals), then I shatter.
Scepter/sword seems pretty good defensively, and yes, staff is pretty good all-around. My problem right now is that I don't have a good damage set, this will be easily fixed though when I find a good staff or sword. Also, yes, traits could help a lot, but I am still relatively low level so I don't have access to good traits yet.