Instead of destroying gear it renders the gear useless (functions as an empty slot) but unremovable (a-la web) for a moderate amount of time long time (15-30 ticks). And giving a +ac penalty (proportional to size of thing dented).

This removes the griefing aspect of being able to trash someone's gear, while remaining somewhat useful in rare circumstances. It'll still be annoying (who wants to spend 20 minutes unable to wear half a suit of armor) but not too horrible.