After giving this some serious thought, you could be the effective health tank from hell for even heroic raids. Think about it: you have 25% damage going to your pet (Soul Link + glyph), 6% flat damage reduction from Molten Skin, 10% physical damage reduction from your VW (Master Demonologist), the sacrifice as a minor tank cooldown, immunity to crits, more armor than any other tank, and a 26% healing buff on yourself. That means you have 41% damage mitigation before armor and your armor is pretty much hitting the soft cap. You spam searing pain and nothing can pull off of you, especially if rogues and hunters help you out just like all other tanks. You also have a charge, a taunt, and the aura that helps with aoe pulls.
Your biggest problem is that cloth gear doesn't have the hp necessary to really tank. Even with rings, trinkets, and neck as stam pieces, it's hard to break 30k unbuffed. However, if they changed the 20% damage to 20% stam or something like that, it would take care of that problem.
It wouldn't even be OP in pvp: it'd be like trying to take out any other tank. High mitigation, low to medium damage, annoying CC. Especially if they took out the snare/stun duration reduction, which I think would be a very good idea.
With current talents, the spec would probably look something like
http://talent.mmo-champion.com/?warl...dmAG,arN,10596 though it might be slightly different. That's in all 232/245 gear, so other people might want to move some points over to the hit talents since you probably lose hit on rings, trinkets, cloak, and neck.