So... Vibes. Okay. I will be coming at this to how the healing kit ties into the rest of the kit.

I will second WHM being the stance swapper. I'd tie it tightly to their healing resources; you could swap quickly for more resources at a DPS loss if need be, but basic filler GCD heals and lower power off globals are still there if you just need to fix a mistake or two.

SCH, given the themes of fairy partner and battle tactician, I would have their DPS and Healing systems mostly separate, much like we have now. If we can have poisons back that would be SCH's theme for damage, while their big heals would benefit from "preloading" them in some way in order to put the "planner" archetype front and center. Fairy would handle buffing and routine healing.

AST would focus on their cards, which would both have buffs and grant them access to their bigger heals. The cards would be in "decks" with each of the six cards, and the healing challenge is making sure you have access to the healing cards when you need them and the buffing cards when you want them. DPS would be proc based, with cards giving them guaranteed procs.

SGE will be closest to what we have now, except with more of a focus on Kardia. There would be many combos with equal average damage values, but different Kardia effects. Since it takes time to go down combo lines, Addersgall can still provide spot coverage, but Kardia Combos becomes the main healing tool.

So rotationally the healers would have different variations on how much healing is coupled with the rest of the kit.