Glaurung said:I agree with Crothian that you should add the Combat Casting feat as a pre-req, and you should require an appropriate Concentration check to cast defensively if this occurs in melee. Other than that it doesn't seem overpowered-a sorcerer would have to be what, 6 or 9th (depending on race) level to even take the feat. The to be effective at all, the spellcaster would have to be in melee combat. Its a very good niche feat for a specialized spellcaster.
-Mike Gill