could probably go either way, I like my scientist though.
Beserk for an extra aoe is really nice even though it still fails a bit at mastery, handy in places like fiesta and chaos tower if there's still monsters around after spree.
Sharp is pretty nice too since it can tack on an extra 26% or so damage to your skill crits, might cover the ac loss a bit. It does need keen at level 5 though, so it'll probably be something you might get a tiny bit later. It also works great with shield breaker.
After the core 2nd job skills are covered (ps, ds, spree, shield breaker) you're pretty good either way.
if it helps, picture of my gunner from a little bit ago, main difference from now is probably just a couple levels: