I'm running a boomkin and 4 shaman, and I'm finding that the boomkin's DPS is actually quite lackluster. My shaman have done well over 500 DPS in the last couple instances I've done. The druid is usually about 150 DPS less with roughly equal gear. I'm generally using wrath spam on the druid and CL/LB/LB rotation on the shaman. I guess some of the DPS difference is due to CL hitting secondary targets often in instance pulls, but still, DPS is DPS.