If your pallies are geared enough to do 3.5k DPS in prot spec, then yeah, you're easily capable of most 5-man stuff. I was clearing heroics with a team that was all under 3000 gearscore rating and the DPS were only pulling about 1800ish on a good day. If I can do it with that crappy group, you should be able to faceroll it if your prot is doing twice the DPS of my DPS spec.