Have you tried blue-green-red-blue-green-red-blue-green-red. Are ppl running away with the debuffs etc? Is everyone following the mechanics?
If so you just need to have a firm cd rotation during ragephases. Stuff like DK using AMZ etc, maybe take in the shammy for extra healing cd?
Fights on normal arent really a dpsrace, specially if you guys are at 500ish ilvl. Does the priest know how to play disc? How to gem etc. Cause i mean having a disc that does dps and heals at the same time is win. Otherwise since that fight has alot of aoe he might be able to help out more as Holy. You could even make the druid go boomkin if he knows how to play it, os tranq is all thats needed anyway. Never had the opurtunity to play with a misty but of what ive seen their "aoe" healing seems kinda nice. Looking at your longest try the healing didnt really seem bad or anything. You do have long fights tho, you can compare to our kill this week
http://www.worldoflogs.com/reports/r...?s=3408&e=3761
under 6 mins. Seeing as you guys are 2 mins over that and still dont kill it i would say it has to be as you stated underperformance.