Nice build. Very well though out. GJ!
1) change vacuus scorpio to mutany. Difference between 50% and 100% WD on non eternal weapon is very small. On your current set up it is only about a 10% overall dmg loss.
2) the change above allows you to switch out your OH for a Vial. 100% ele crit when ever you want saves you the 2 wasted ele crit affix that allows you to invest into better affixes
3) i recommend changing the 2 ele crit for ED+ or 2 guided shot for dmg (preferebly guided shot due to cubic growth), 2 time warp procs (basically triples your DMG since you have high OH DMG + Cosmic power) or things like +5 stagger and +5 ensnare to give more lock down (rooted, stunned and knocked back enemies will have a very tough time getting to you).
Vial helps your build so much that 10% DMG loss is not a big deal. Blue orbs and MP potions can help you recover the extra EN.