Hmm. Well, if I had to, I'd probably nerf outgoing DPS and buff the healing modifier, and give the slashing debuff they bring to the other tanks, as well. So something like a 30% hit to skill potency and a 25% buff to the healing modifiers, so the amount of incoming healing would be about the same, just the damage going out would be lower. Combined with handing the slashing debuff out to other tanks, this could go a long way to making Warriors less essential to raid comp.