Some of the top damage dealers ironically seems to be the barb...
The things is rares have a 6 affix limit, that means you gonna have to always sacrificing something:
Ironically the best thing to sacrifice for dps seem to be lifesteal/LoH/crit damage. So for dual wielding one handed weapons, this is about as good as you'll ever get.
*Secondary Split Stats (Main + Vitality)
Now all you can do from this point forward is sacrifice. You could replace socket with a perfect damage cirt damage roll? Here's the problem when it comes to legendary weapons, having an extra "Cool" effect, you loose one of the more rewarding affixes.