Honestly, at this point, let's just do it. We go through with the philosophy that WHM remains largely unchanged, and the other three healers are all reworked to have more engaging rotations and a more balanced disparity between offensive, recovery, and supportive actions. Meanwhile, here's my proposition for WHM:

LV 92: Glare IV - Potency is 330
LV 92: Enhanced Afflatus Misery - TRAIT - Afflatus Misery potency increases to 1320
LV 92: Dia II - Initial Potency is 70; damage over time is 70
LV 94: Purification - Usable while Asylum is in effect and replaces Asylum on the hotbar. 300 potency OGCD heal to all allies standing in your Asylum.
LV 96: Budding Afflatus - Adds 1 lily to your healing gauge. OGCD action on a 90 second cooldown.
LV 98: Enhanced Tetragrammaton - TRAIT - Increases the potency of Tetragrammaton to 900.
LV 100: Afflatus Conservation - GCD action that applies a 250 potency barrier to self and all nearby allies. Consumes 1 lily, nourishes the blood lily, and has a cooldown of 90 seconds.

Nothing else changes. We leave WHM at that, rework and revamp the other three to where their gameplay is varied, not unlike the tanks in terms of depth, and each offer some type of unique utility, and we just see what happens.