A Healing Class Without Mana?

The monk class will bring us another healer entering the mix and it will be another healer that uses mana.  As it is there are tanks that use various types of resources and damage dealers that use various types of resources.  Will we ever see a healing class with a different type of resource?

Lets take a look at the current resources we know, except chi as I do not have enough information on it to make any judgements, and see how healing might look if healers used those resources.

Runes:
Pros: It would make for extremely dynamic healing as you would need to rotate spells to use what runes where available.  For people looking for a complex healing set up this could be it.  Having runic power as well would add an interesting two resource mechanic to healing.
Cons: It would really leave rune healers at a disadvantage in those heavy healing moments where they might need to spam heals.  If unholy runes where for AoE spells you would be left only being able to hit two and wait.  If frost was for big heals you would only be able to cast two and pray.
How it can be adapted:  They would need to make the runes act differently.  All runes would need to be the same and the spells you choose would use runes and set a cooldown on them based on the power of the spell.  A small heal would have the rune reset in 2 seconds and a big heal 10 seconds.  Perhaps a major cooldown like divine hymn would put one on cooldown for 30 seconds leaving someone with only 5 runes to work with.  Runic power could be used to empower abilities for bonus oomph or refresh certain runes for a cost based on how much of a cooldown they have left.
Could it work: As is, no, it is not really possible.  With a revamp of sorts like I mentioned, it could be a fantastic healing resource.  Use all your huge spells and be screwed for some time, or balance big and small and cooldowns to keep healing flowing.  It could very well be an exciting way to heal.
Will we ever see anything like it: Highly doubtful but it does have some potential.

Rage:
Pros: If it is based on damage you or people you are with receive it could mean unlimited resources. It would most likely need to require you to buff someone, or a few people, as the main generator of rage for you meaning in most cases it would be put it on the tank, a set it and forget it mechanic.
Cons: If it where an unlimited resource it would take some of the excitement and skill out of playing a healer.  It would also leave the possibility of rage starvation on the table for another person in the party, never a good thought and even less so when that person is your healer.
How it can be adapted: You would need to have some abilities that generate rage like shields for disc priest or some abilities that are flat out free.  Perhaps even work rage in reverse where you generate rage when out of battle to get back to 100 so you can use it to buff and preroll HoTs and such.  During battle you would regenerate it from damage people take in battle.
Could it work: I do not think it could work, at least not as we know rage, there is just too much more to add into the game to make it work as we know it.
Will we ever see anything like it: I would guess never is a solid answer here.

Energy:
Pros: It constantly regenerates which means you can go endlessly.  The combo point mechanic would also create a way to do some massive heals which could also be really good.  Unlike DPS where you use your combo points I could see healers getting to a 5 stack of points and not using their big heal but saving it for that moment later when they need it.  This would create a very exciting way to heal.  Use it now or save it for later.  The smarter healer will always know the answer to that question.
Cons: If you have ever played a rogue or a cat you are used to hearing "need more energy" three seconds into a fight.  As a damage dealer it just means a DPS lull but as a healer if you hear "need more energy" three seconds into a fight it could mean dead people.  With damage dealers it is annoying, with healers it could be downright painful.
How it can be adapted: Adding a few small energy generators into it could help a great deal.  Every time an HoT tick crits you get 2 energy.  Every time you heal on target with max combo points you get double energy generation for 5 seconds.  Have haste effect it more generously than it does DPS.  Things like that could help.
Could it work:  Yes it could, and it could work very well. Using mechanics like giving the bonus energy regeneration when healing someone with more combo points on it could make for a very interesting healing dynamic.  It would also need to count combo points on everyone and not just one target to be effective and then have all combo points fall off instantly when you drop battle, so you can not carry the 5 combo point buffs into battle.  It could work very well.
Will we ever see anything like it:  I would love to think so.  This one has amazing potential when it comes to healing.  There is so much that can be done with it if they worked on it.  I think if they ever add another type of healing there is a fair chance this could be the way they would do it.

Focus:
Pros: Endless healing potential.  If it is like focus is there would be a focus regeneration ability.  It would most likely be a small heal but even at that it would mean that you can constantly heal, even if only a small one, and never run out of resources.  While focus might hit dry spots it is an endless resource that you can regenerate on your own.  As far as pros go, this is a huge pro.
Cons: Endless resources can really soak the fun out of it.  Ask any healer if things get easier when you do not have to worry about mana and 99 out of a 100 will say you're damn skippy it does.  While this can be fun sometimes I think an endless resource healer would be a bad thing for the game.
How it can be adapted:  Make the focus regeneration thing work differently.  Instead of having the small heal as the regeneration heal make it just a free heal.  Leave bonus regeneration to something else, maybe even an instant cast damage dealing spell so the healer has to mix it up here and there.  If the focus bar where 1000 instead of the 100 we know it is I can see this working better.
Could it work:  If the endless resource part of it can be removed then it can work.  You can't make spells cost too much because those spam moments will be required but you also can't let someone get back up to full resources that easily being you have to make the cost of the spells so much lower because of those spam moments.  If a balance can be found between cheap enough heal costs to handle heavy damage moment and focus regeneration then it could work.
Will we ever see anything like it:  If they ever add another version based on something we already know and it is not energy based, it will be focus based without a doubt.  I can see this as something we might possibly see some day.

In the end you have to ask, do you think we will ever see a healing class without mana?  My answer is no.  All the above answers I gave, even the bad ones in the con sections, would still leave all other resources leaps and bounds better than mana for one reason and one reason only.  Mana is a limited resource, none of those other things are.  Removing the need to manage mana seriously changes the whole concept of healing.

If they where to create a really tight system with lower heals but many many more of them needed then I could see it being possible to add one of these other types of healing resources but even at that you have to think where would the balance be?

If they make the heals small enough to offset the concept of unlimited resources then they might be too small to be an effective healer.  If they make the too high then they are making it way to powerful because why would you heal with someone that can run out of mana when you can do it just as effectively with someone that will never run out of their resource.

All these other options that might sound exiting would just be way to hard to balance.

Because of that I do not see a future for us having a healing class that is not mana based.  I might see a future with a healing class having another resource, but it would be handled just like mana is.  They would just call it something different.

Do you think the day will ever come when we see a healing class without mana?