Design the next WoW hero class

The third expansion of World of Warcraft hasn't even been announced yet, and is unlikely to arrive before 2010. But we can be pretty certain that it will contain at least one new hero class. And it will probably be a healer class; Blizzard said they designed the death knight to fix the tank shortage, so a healer hero class to fix the healer shortage would be a logical next step. We also know some other hero class design principles: They should feel epic, but be more or less equal to the existing classes in power, thus they shouldn't make existing classes obsolete. And they can be somewhat more complicated to play, as new players won't be able to choose such a class for their first character. So how would you design such a healer hero class for the next expansion?

The first question to answer is how the new healer hero class would power their heals. All existing healing classes in WoW use mana for heals. And just like the death knight doesn't use mana or rage, but a completely new mechanism, it would probably be a good idea to design a new healing mechanism for the new hero class. That would have the added advantage that you could base the power of that new healing on a stat different than spellpower, and wouldn't need mana regeneration, thus avoiding the new class to compete for the same gear as the existing classes.

A related question is what else but healing the new class should do, and what connection there will be between his healing and his damage dealing. WAR has healing classes which in various ways power their healing by dealing damage first. Something like a melee healer, who collects something similar to a warrior's rage by combat, and then uses that for healing would be one possibility. The downside of that would be that such a system would probably not be sufficient for being the main healer in a group, so maybe we need to come up with something else.

The hardest design question is how to balance that new healer hero class against the other existing classes. A lot of healers solo in a different talent branch than the healing one. But if you give the new class one or two dps talent branches and one or two healing talent branches, you risk getting a lot of new dps characters, and not as many new healers as you wanted. It took me some time to realize that Blizzard did a clever thing with death knights, enabling them to tank in any of their three talent branches, being frost doesn't make them much better tanks than being blood or unholy, it just changes the way they tank. So I think a class with some close connection of healing and damage dealing would be good, having no clear healing and not-healing talent builds.

So how would you design this class? Ranged or melee? What kind of armor? What kind of damage and healing? How would you make sure that the class heals good enough to be main healer, without being gimped for damage? And how would you make sure not every current healer deletes his character and rolls one of the new class? Go ahead, post your ideas!