One class that I'd really like to see is what i call a "Dragon Tamer". Given the relationships that the aspects have with the Old Gods per Cata and the chronicle, I think it could fit.
Essential 4-5 specs, each one based on one of the aspects. This one would thematically work as a third mail wearer as well (which is desperately needed imo)
1) Heals: green aspect; kind of mistweaver with jade statue interplay between you as caster and green dragon as support caster
2) Tank: red aspect: one of three ways to go with it 1) you become a red dragon and self heal a la death knight, 2) you stay non-dragon but take on aspects of the life aspect to keep yourself going, 3) you tank regularly, utilizing a red dragon guardian to occassionally buff you
3) RDPS: blue aspect: caster with pet, with spells focused on a mixture of the magics as opposed to the segmented style of mages
4) MDPS: black aspect: for this one, I think it would be cool for you to not have a pet, but rather become one of the melee hitting black dragon peeps
5) (potentially) heals/support: bronze aspect: some kind of something involving aspect of time, absorbs, restores, etc--if not a fifth spec, then maybe a couple of class wide cooldowns that incorporate the bronze flight)