Ok so... change nightstalker to shadow focus, change shadow reflection to venom rush, get either 2 slow weapons or put the dagger in main hand, fast mh slow oh is good for aoe, for single target combat you want two slows. As someone said before get glyph of disappearance, more vanishes = more ambush = more damage. You also want slice and dice up 100% of the time and revealing strike up 100% on your target... getting an addon to track them and your insights will help. use kspree and adrenaline rush whenever you can as soon as you can. hopefully that may help a little.
eh just saw you fixed most of that stuff :P
if you can try get 4 set... is awesome for combat