Your build is way too discipline heavy for your 30 max discipline. Hell, even mine isn't as discipline heavy, and I have 50 max. How much do you think you need Gloom? Do you use it because you tank damage while fighting? I tend to avoid almost all damage by using vault, which is much easier on the discipline. It's not completely foolproof, but I avoid most hits, which is good enough.
How good is your kiting? I find that if you can kite pretty well, and are good at vaulting at the right times, you don't really need shadow power.
I don't think you need Archery, not unless you decide to use a bow. Since CC and CD complement each other, you would want a lot higher CC than 16% in order for the 50% CD bonus from archery to really be beneficial. Especially since you're using a 900 DPS crossbow in Hell, you should be melting things already.
I don't like your choice in Spray of Teeth. I think it's better for minimum of 40% crit chance. Otherwise, since you already have AoE covered in ball of lightning, I'd go for single target damage in Devouring or Puncturing Arrow.
I wouldn't worry too much about upgrading; I would say your gear and stats are good enough, as long as you can play smart and avoid damage properly. Are you making sure to read the affixes of every elite pack before you engage them? It may be time consuming at first, but you get used to it. At this point, I do it almost automatically, without it hindering my pace at all. (Although maybe you could stand to find a resistance piece or two, to help that all res.)
Edited by Bottle#1907 on 2/16/2013 5:47 PM PST