Different classes have different abilities, talents, gear and resources. It is probably naive to assume that we can get fire Aoc Gold Mages and balance Druids to do the same DPS down to the second decimal place. Encounters are built differently. Your personal DPS is unlikely to be the same from boss to boss because of the specifics of that encounter. Likewise, another class may do higher DPS than you on some encounters. It's hard to come up with "average DPS" for a class as much as everyone tries.