To say that shaman can’t hit high enough DPS on a single target, I think that is missing the idea behind shaman? It is the only class who excels at multiple target DPS.
Serious question, my brain is not awake enough yet to form a logical conclusion:
Player A is doing 70k dps as a shaman while attacking a group of 3 mobs.
Player B is doing 100k as a runemage while attacking a comparable group of 3 mobs.
Who completes the task of killing the three mobs first?