Yes there is plenty of room to make other healers, one just needs a bit of imagination. I wont get into naming FF classes just pointing out mechanics (gimmicks) from other games that could be utilized:

6 ideas off the top of my head are:

* A healer that uses honest to goodness AoE auras to buff and heal, stronger buffs/heals the closer you are, weaker the farther away you are.
* A turret/totem healer, places down nodes that have buff and healing effects, can link nodes for greater effect.
* A beam/chain healer, lays down a buff that allows thier heals and buffs to ricochette between other players, a bit challenging since the ricochette effect is random at times.
* A healer that uses a mechanic not that much different than ninja, they combine glyphs or symbols to create different healing effects.
* A healer that get in melee range, thier strikes land a debuff that allows all thier allies who hit the same creature to get healing and buffs from that creature.
* A healer that is kind of a controller, one who lays down ranged debuffs and to that effect small but functional ammounts of healing come from the afflicted target.

Disclaimer: I am not suggesting these classes to actually be put in the game, which is the reason why i have not named them. I am not actually asking to put more classes in the game, this is just to facilitate the discussion as it has been presented. I am not suggesting that the game be changed in any way or mechanics to be adjusted from what they are, however these are ideas that i see as the realm of possibility with the mechanics we have now. Lastly, I also realize that several of these ideas may be redundant, again the idea is to help stimulate creative thinking and not about any form of competition over brainstorming.