Unsaveable,
The current trend is that Resto Shamans are about ~5-12% behind other healers (on average). There were a couple of fights where Mistikk was keeping up, and some falling behind.
From what I saw, there were about ~16 players in the raid? For this you should be able to get by with only 3 healers (On average 1 healer for every 5 players). With 4 healers you'll find that one healer will appear to be underperforming because they're bored. See final note below, but that seems to be the Shaman in Warlords so far. I wouldn't be surprised to see that Mistikk's able to pickup the slack fr