I had someone quit a Susano party last night because I joined as WHM and the other healer joined as SCH. Gave us the choice of swapping to AST or watching him leave. Luckily he was just a jerk and we got a replacement DPS quickly enough, but this is a thing that is currently happening. A couple statics in my FC were toying running double AST, but I'm not sure if that fell at the planning stage or not since Omega isn't out yet.