The idea's been tossed around a bit, I posted it in another thread, but it's not gonna be seen on the 7th page. It's not that complex, but would really help out a lot.
The idea is for bullets that are capable of piercing deflector and hitting the target with full (or maybe 80-90% if thats too powerful) damage. The deflector is not effected, it doesn't go poof like shelter from a spirit modded bullet. The point is to provide a way to deal more damage to buffed chars while not royaly fucking them by stripping their defenses.
I believe this would be a much better answer then the spirit mod.