If you want a bunker, why not just use some skeletons? Why would the aloof uber-necromancer hang around with the rotting, smelly, bloodmad ones? It just seems a bit weird to be able to have a unit, but only one. Either they should be normal core or rasie only IMO.
I think they should stay at toughness 4, that's more justified fluff wise than no unstable I think. However there would need to be some serious limitation on your ability to resurect them if you want to keep them as unstable, because otherwise you get the ultimate tarpit. They have to kill 20 guys in one round of combat, otherwise you can just raise them back.
I like the whole idea of the revenants, but I can't help but feeling that making them unbreakable is too good if you can have a unit of twenty in the first place. Maybe if they were raise only and you could only raise small units, but otherwise...
I think they should stay at toughness 4, that's more justified fluff wise than no unstable I think. However there would need to be some serious limitation on your ability to resurect them if you want to keep them as unstable, because otherwise you get the ultimate tarpit. They have to kill 20 guys in one round of combat, otherwise you can just raise them back.
I like the whole idea of the revenants, but I can't help but feeling that making them unbreakable is too good if you can have a unit of twenty in the first place. Maybe if they were raise only and you could only raise small units, but otherwise...