Okay, really, I'm 99.9% sure that sanctuary + dissipation shield is just a bug and it will get fixed. That's why we have beta testing rather than just launching the cards directly into the game
So, assuming that will be fixed, let's look at the rest of it.
I for one feel this card is unbalancing, even assuming dissipation gets fixed. To explain, let me go back to the earlier example of sanctuary versus discord:
If sanctuary comes out first, then discord is completely useless. It will do some damage, but the healing from sanctuary will help with that. If discord comes out first then it will get maybe 1 or 2 turns before sanctuary comes into play and crushes it.
On top of that Discord is a weapon, and thus you can only have one in play, whereas stacking sanctuaries is pretty similar to stacking SoGs. So a discord deck will have maybe 2 copies of discord (unless it's a flying weapon deck) whereas most decks using sanctuary are going to pack a lot of them. Even against decks that don't use denial cards it's almost as good as SoG.
What's more, sanctuary doesn't just stop discord. it stops discord, and devourer, and black hole, and nightmare and silence. This one card will wreck an entire deck, so comparing it versus just one of the cards it will counter is a bit silly.
The nerf suggestion I liked the most so far is giving it a turn limit. As it is now it's a hard counter to certain decks, that's still a good card versus any deck you can come up with.