Bad hunters do total crap DPS..IMO, hunters are very strong because of the ability to DPS on the move and the overall simplicity of gameplay in SV and BM (didn't try MM, so can't tell if it's just as braindead as the other 2 specs). Those 2 things lower the skill-cap of the Hunter class to a point where every single individual automatically becomes rather good when playing hunter.
What this means is that in mediocre guilds consisting of both good players and baddies hunters will usually be at the top. In strong guilds, where people play their classes at their best (or close to that), hunters have no chance to compete with OP classes/specs. However, affliction locks will be severely nerfed in 5.2, so I see no problems there. And arcane's DPS is easily ruined by movement, so they can't be top in all fights and actually have to be quite good to pull out big numbers where movement is involved, so I see no problems there either.
As for the lack of cleave - every class in this game has some weak spot, that's part of the class system, just deal with it.