Let's discuss what the best possible 2v2 combo including a Shadow Priest is.
Obviously, it won't be viable considering how terrible Shadow Priests are right now, but if you absolutely had to 2v2, what would be the best combo?
Right now, I'm leaning towards Retadin + Shadow Priest.
The main survivability problems come from melee, so Blessing of Protection would at least give some time to throw out some damage and get a full set of DoTs up.