Karazhan GearFollow

Alright, so my guild just started Kara and I looked up all the upgrades I could get in there.

My armory is http://armory.worldofwarcraft.com/character-sheet.xml?r=Argent+Dawn&n=Lineli

And I'm wondering about two things specifially, shoulders and my gun.

I currently have MAma's Inssurance (Http://www.wowhead.com/?item=30279).
I'm wondering whether or not the Xavien Stilleto from Illhoof (http://www.wowhead.com/?item=28659) will be an upgrade? Considering I have low AP already not to mention plenty of Hit would it be wiser to stick with the Gun?

The other thing is my shoulders, I have Blackened Leather Spaulders(http://www.wowhead.com/?item=29148) and am looking at Bladed Shoulderpads of the Merciless (http://www.wowhead.com/?item=28755). Again in my mind its a matter of me losing already low AP.

Any thoughts or suggestions would be great, especially about the balance of my stats.

1461 AP
206 Hit
19.64 Crit %

So the AP loss doesn't matter that much compared to more and more hit? At what point will I have too much hit for the amount of AP and Crit I have?

Your AP is fine for now, but there is no reason you should pass on either of those pieces of gear. They will, in the long run, be upgrades.