I remember some angry ranged DPS, probably a warlock, complaining on MMO Champ that only selfish players were melee DPS. At the time I thought, that's ridiculous, I play melee and don't consider myself selfish, but after thinking about it I have to concede he had point. On most fights, ranged DPS handle the mechanics whereas melee DPS simply tunnel. It stands to reason, in general, that your raid's better players should be ranged DPS - again, in general.
Tanks, though, seemed to be in a good place, where skilled players were not really wasted. To be an effective tank there's not all that much skill to it, but to do the later heroics, or to progress on content when not greatly overgearing it, there were many points for failure. Most of us in this thread would probably argue that content should be tuned harder, but for an expansion where tanks were more than afkbots, it was a good start. You could definitely tell when your raid had a skilled tank as opposed to a mediocre one, and an excellent tank could truly shine.
But if they want to renege on this philosophy, and return to the old days where tanks are simply meatshields, then it doesn't make much sense for a good player to be a tank, unless there's some intangibles involved (raid leader, who finds it easier to lead when tanking for example). Hence I'll roll mage if Celestalon delivers on his promise. Why waste your talent doing something which almost anyone else can do?