Spear Shards currently has a problem. It is a ground-targeted AoE skill with a single-target Disorient/Stun. When there's more than one enemy in the area, which one gets CCed is pretty much down to chance.
My suggestion is to make Spear Shards an enemy-targeted skill, dealing its AoE damage to an area surrounding the target. This will allow you to choose who to CC amongst a group of enemies, and also serves to make the skill easier and less clunky to use; especially if you're using it against just one enemy.
The downside of this is, of course, you can no longer place the AoE exactly where you want it to be, and some may see making the skill easier to use (not having to take into account AoE size and casting delay against moving targets) as a downside as well. I think however that giving us control over who to CC is more important.