-50% to the bonus AP and -1 BB/WP is probably enough of a nerf. Subtracting 2 from BB/WP sounds a little harsh, but just 1 is a little light. Maybe -2 BB and -1 WP? Not the most elegant solution, but might be a good medium. I'd figure GC would affect the body more than willpower. Possibly it could even just be -3 BB and no change to WP so you have to be extremely careful of fire, poison, knockdowns, etc, but you're not any weaker to the likes of charm and mute. It'd take 6 ability points to have even no penalty, and maxing BB out would basically be impossible.
