I like this idea, but it would create bottle-necks and the type of min-maxing Yoshi and the CS3 team have been violently railing against for years. In part because it would become so hard to balance. Giving a 'prestige class' (so to speak) anything meaningful means they have to be meaningfully balanced, which ... frankly they're struggling to balance the classes they have in the game already.

That aside I actually do like the idea. That or the old EQ AA system. But... I think that's also unlikely.