...or other stat damage. Just a thought because currently monsters and players can obtain various types of DR for HP damage. I haven't been playing since about a year ago, so I don't know if this has ever been discussed yet, so I'm just throwing this out.
I just noticed all the threads about stat damagers and how they were arguably affecting the balance of the game, so I thought this might be a decent idea that wouldn't require a direct nerf to WoP per se but rather an indirect method to reign in such weapon's apparent dominance. I'd think you'd want to keep such an addition to defense options somewhat rare at first just to sort of test it out. That way stat damagers would still be nearly as useful as they are now, but you could temper some encounters to keep them as challenging as you'd like.
Taking it a step forward, you could continue with weapons that could bypass such stat DR (maybe transmuting, maybe something else), but that would logically make the weapon much more valuable and hard to come by.
Cheers

-Aeyr