@ yokumgang I disagree that its going to be an Archdruid. I seem to recall a blue post not to long ago say that they didnt want to create and Archdruid because it would be to similar to current druids.

I do however agree that it will be a healer. I cant imagine what kind though, seeing as most of the old warcraft classes have been created or incorporated into other classes (blademasters are the ones I see alot of people cry out for, but thats the arms tree of warriors).

I predict that it will be a plate wearing healer, but what its style would be I cant imagine with out thinking of a healadin.
I think it will wear spell power plate for the simple fact that blizz keeps stating that they despise making gear that only one class can use (hence druid/hunter weapon homogenization, tanking plate homogenization, and hunter/shaman gear homogenization), yet only one SPEC can currently use spell power plate.
It is only logical to conclude the new healer will be able to wear plate, or else they re-work paladins to no longer wear spell power plate in order to achieve their goals of homogenizing the gear.