How about penalizing bashing things open by adding a *dazed* debuff that reduces your AP and/or initiative? Whenever you try to bash something open there'll be a slight chance for it or it gets applied every time. Bash more = higher penalty. That debuff could also only tick down in combat so you couldn't just wait it out.
You won't bash during a combat, so you don't care for AP at all.
Bashing stuff open is already painful and annoying. Giving a daze effect you could aswell just make everything unbashable.
