Very complex. I can appreciate the write up and effort that went into it so a +1 to all posts.

Thing is kinda that healer is *mostly* okay, and for game development and game design there is a "KISS" approach: Keep It Simple and Stupid.
Completely overhauling jobs is not something that has ever been done, and likely will not happen. This is a GREAT what-if scenario, but I don't have high hopes for any of this actually even being considered because it's just way too much work and doesn't address why healers are 'optional' in the first place, and that reason is: tanks have too much sustain for themselves AND party.

What I would instead recommend is proposing ideas for an immediate win™ scenario.

For example:
- Removing all healing and shielding abilities of tanks. They can only mitigate and reduce damage for themselves and party as a tank should, but not heal. Instead, what they should do is increase their healing received, or get bigger mitigations. But for real, remove all of the heals and barriers that tanks can apply to themselves or partymembers. This is a healer's job and it shouldn't overlap. Period.
- All healers should get a damage optimization if there are less heals to do:

WHM: overcapping on lillies = feeding the Blood Lily.
SCH: Energy Drain is great as it is. I would maybe add in a combo, similar to SMN's Fester/Necrotize that is a small potency oGCD that gets added after using Energy Drain. Maybe also can spread Biolysis DOT?
SGE: Toxikon gets more potency from 360 to 420, making it a DPS gain even on single target and you WANT to use these in bursts. Addersgall overcap = automatic Addersting stack if possible. Possibly Rhizomata can get an additional proc that if used on full Addersgall stacks, it also refills ALL Addersting.
AST: gets Redraw ability back with a 60 second cooldown, but only applies for Minor Arcana. Can change Lady of Crowns into Lord of Crowns and vice versa. Redrawing the minor Arcana increases its potency by 50%. (redrawn Lady into Lord = 600 Potency damage. Redrawn Lord into Lady = 600 potency AOE heal). Also helps with the first raid burst right now I think, which is always kinda forced to be a Lady.