In a world where you are making dispells being a meaningful choice, the only way to really shut down to mage is to use dispell's and such on cooldowns, which actually makes Mages more powerful since these sorts of abilities cannot be liberally spammed like they could and do cost a meaningful amount of mana. Yet Mages have spell steal and they don't seem to run out of mana.
Mages have no counter-play, meaning there's no weakness for other classes to exploit, because mages have the 4 pillars of a successful PvP class in excess. There's no specific glaring weakness that a mage possesses.
Mages have a excess amount of:
Something has got to give. You can't give a class all of these things and not have glaring weaknesses. What makes me upset, is that blizzard hasn't came out and spoken about this. From this players point of view, it looks like they think mages are fine, and so aren't taking action. Which is dead wrong.