it was barbablo long time ago in d3 official forum(even before 1.0.4), lots of people complain, blizzard have tried to buff other classes, but just by very little so other 4 classes have no way to reach the level of barbarians
now more than 40% of paragon level 100 was barbarians...
imo, blizzard tries to balance out classes for pvp and farming...some other class might rule when pvp is out, only IF barbarians rule both PVP and farming....