It could be interesting to see a DPS healer that uses Drain type spells that heal people in the party for a portion of how much damage they do. Then perhaps some type of spell that lets you lower your HP to increase the maximum HP of a target temporarily.

I mean there's plenty of design space for additional healers. The problem with Ast is they tried to make it a white mage and a scholar that switches with stances, but couldn't make it as good as either since Regen and Stone III would be broken on Sch while Shields and Bane would be broken on Whm so it ended up without the best of either.