I don't even get what you're mad about. Are you just mad because you enjoy being mad? If it's the offensive capability of healers you're worried about, I haven't seen any huge changes to that except I guess Priest Level 90 talents. I don't really get this thread.
Start with what you find fun and enjoy about healing right now. Is it that you don't have to look at who you're healing for many spells? Or that you're worried raid damage will be the same as it is now? If they want the new healing model to be a success, then they can't have raid damage being dished out like it is now. At this point you don't have to worry about extreme, completely unpredictable raid damage like we've had through the last two expansions.
That said, there hasn't been any truly instakill-type, random raid damage in Siege of Orgrimmar except at Heroic Iron Juggernaut sometimes. Heroic Sha of Pride gets tough at the end, but your damage dealers should be using their own stuff to stay alive too. In the patch notes,they said they're deliberately shifting more of the responsibility onto healers, but they're not just gonna make it harder for no reason. For better or worse, they want to keep the game accessible enough. This means to keep healing at where it is, or better, they will loosen up on raid damage.
Edit: Okay, I forgot about Thok too. I haven't done him on Heroic, but I remember when he was challenging on Normal. That one's really bad too. Watcher is aware he's like the epitome of everything wrong with current healing that they're changing. He literally said the Thok fight would not exist with this healing model. That makes me think they're going to do something extremely drastic in 6.0, like cut all damage to half potency of current.