There really aren't any more plate healers that I can think of. However, there may be a plate DPS that uses spell power, BattleMage. BattleMages are a mix between a mage and a warrior (Just like how pallies are like a priest and a warrior) That is one class I would definitely play.

Battle-magi are a recurring joke between me and a friend after I went OOM in SSC and started meleeing Vashj, desperately trying to keep my DPS respectable.

I can't see that being the hero class though, since they have no innate healing abilities. Archdrood seems more likely.

i'm still hoping for some kind of monk/cleric hero class. let them fight hand-to-hand with fist weapons or staves and also have a healing tree. something like a rogue-combat tree, a priest-discipline tree and then a holy tree. It would be awesome to run up to a mob, give it a few uppercuts, then stand back and heal yourself or your party members.

@ 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.

I think the healer plate issue will be addressed by eliminating spell power and attack power into a single stat called "power". It seems to have worked for damage/healing.

To go along with a change like that, a monk would be perfect. A cloth wearing melee DPS/healer.

I'm thinking demon hunter ...

we've already seen em, and if its a demonic invation into the emerald dream OR meal it'd make sense

Blizzard has said that they want to change holy paladins eventually so that their healing spells scale off of melee stats and they can share gear with all of the other dps plate classes and there won't BE any more spellpower plate, but that it's too large of a job for a mere patch. So I doubt we'll see a plate-wearing caster in the next expansion. We're more likely to see spellpower plate removed entirely.

Especially since our first hero class was already a plate wearer. I'd imagine a leather or mail-wearing magic class similar to a druid or shaman. After all, there are 3 cloth-wearing classes, and (now) 3 plate-wearing classes, but leather and mail are still at 2 each. Aa new class should wear either leather or mail.