I don't know if this has already been said as I don't feel like reading through 55 pages of arguments, but to me I think the reason there aren't any new healer classes coming out is because as far as existing jobs in the Final Fantasy universe goes, there aren't that many to choose from. They even had to completely make up the Gunbreaker class to introduce a new tank. Dancer would have been a good choice for a healer role and I am a bit disappointed that it isn't, but the only other class I can think of that could be classified as a healer is Chemist and I can't think of a way they could implement it and make it work.

And technically Red Mage doubles as a healer even though it's catigorized as DPS, it can heal fairly well if need be. Dark Knights aren't wholly tanks either as they can also DPS if needed. I would kind of like to see more dual-capable jobs like those in the future.