do hunters do the most dps? sure, maybe SP stacked dot spamming locks can do more, but hunters have typically the top slots in each game
but there are a couple things that don't make them as OP as they seem:
pugs typically don't have healers
dps does not mean victory
yes, hunters are overpowered to a degree, especially in pugs, but when you get closer and closer to teams which have more and more twinks with more and more class balance (such as with solid FCs, CC, healers), hunters just become a good DPSer and not really an overpowered class at all.