I did Ragefire at 14 (pally + 4 shammies). I remember the trogg pulls (and especially the even larger pulls of cultists near the end) as hitting pretty hard. I just had to be careful to heal early, and not wait for my tank to get to half health. Also, even with only 2 DPS, you should be able to kill one of the troggs before they reach you. So you might consider just ignoring one (perhaps one of those caster types if they're part of the pull), and having DPS burn it down, while you judge right on a second then quickly switch to the third and melee it once. That makes the three pull a two pull before they've really started hitting the tank.