I'm not sure I like Shield Specialization. On one hand, love for shield users is hard to come by in DnD. Also, as a general rule, attack bonuses start to outstrip AC anyway.
However, a character using an animated shield could (technically) benefit from the feat, rendering the reward for using a shield moot. Also, increases in AC tend to keep certain types of encounters from working well. It's much harder to threaten characters who make significant investments AC with larger numbers of lower CR enemies, as opposed to fewer, tougher monsters.
We'll have a Duskblade in our upcoming game, plus a few characters who are going to pick up some of the high level feats. My monk is definitely taking Water Splitting Stone, and my wizard has Arcane Thesis so she can use some metamagic with a high level spell although there hasn't been a good time for her to unload with it yet.