Sorry can't help you, I useally play as a Guardian but your not missing that much, I've never found it extreamly useful. But it is a nice feat to gain.
Critical Strike (As far as I know) increases your chance of a "Critical Hit" which is basically a luckey shot that you get in for extra damage on your oppenent. I play as a Guardian or a Sentinal and I almost always get Critical Strike as one of my first feat. I like it.
That's hard beacuase in KOTOR 1 I spent most of the game in battle armour I picked up all the way back on Taris. I can't stand the Jedi Robes in KOTOR 1. As for KOTOR 2 I'm always in robes. :cool: