I think that, in the end, I'll stick so Staff and Scepter + Pistol. Staff is good for AoE effects, boons and conditions and Scepter + Pistol works well when I need to focus on one enemy. Plus, Phantasmal Duelist really is great. I just finished my mesmer's personal story. He's level 11 and would start buying traits if it didn't cost 10 silver. I think I've got the hang of the class.