With dual wield, you have a %chance to perform a dual-wield attack. Every one of those attacks multiplies your damage significantly. The more frequently you get those attacks, the more damage you do. Fast attack weapons are your best bet as a dual-wielder for raw damage output. It won't show up on your DPS, but you'll notice it right away in game.
Also, you've missed a few opportunities, like lucid dream and temporal rift. And since you're dual-wielding, buy out trance of convalescene and try putting just 1 point in trance of empathy, and spend the other 5 in better skills. See how that plays for you.