I noticed that some people are saying to go with 2 set 2 set which I disagree with. The prayer of mending 4 set bonus is amazing. I pair it with inner focus and my trinket and can throw up a 303k crit greater heal (with a 130k absorb). So please don't sit here and tell me that we have no survivability.
If you would like to check out my rag tag gear for right now you can (it's mixed becuase I need to stop gearing for shadow and switch to disc). I seem to be doing fine. I've dueled some OP warriors that have the heroic wep and in full PvP gear in my guild and I last 10x as long with gear than I did with little to no gear. If you have any questions please post a comment and I will try to help.
BY NO MEANS.... am I even close to an expert, but I seem to be having some luck with disc right now. I think priest are broken yes but If I can help out somehow just let me know.