DR 15 would fit with +3 weapons. And it's not likely that they'll be facing many nonmagic weapons anyway, so we can penalize adventurers who aren't using them.
Climb, Intimidate, Listen, Sense Motive, Spot. Climb for the giant form? I don't see these performing or crafting much any more.
Due to reduced Str, we're going to need to change all those feats except Iron Will. Any ideas?