Combat Option: Active Shield Defense.

[Primitive Screwhead]

I also like the sacrifice your shield as a last ditch effort to avoid an attack. I would like a mechanic that would allow one to succeed or fail in this. Like an attack roll vs the attacker touch AC or something. If you succeed you intercept the blow, and the mechanic for bashing though the shield takes over. This would gave a nice cool factor.

I figure the cost of the action, AoO or Action point, plus the probable destruction of the shield is enough of a balance. I would only add a check to see if the block is successful if I remove the cost. Also, adding a check adds another die roll to the equation, something I try to avoid.