Every problem with the current iteration of healers.

[Gaethan_Tessula]

For me the three biggest issues with the current healer design are:

Lack of reward for good gameplay
Examples of 'reward' are DRG's Raiden Thrust, BLM's Polyglot gauge, or 4.X SCH's Quickened Aetherflow... just something that needs to be thought about / paid attention to and gives you something nice in return. WHM lilies are not an example of this as they require neither interaction nor attention.

They aren't now, but they COULD be. With some development, the lilies could be the springboard for a spread out "rotation" of sorts that eventually leads to misery, has exciting spells to use in between, and rewards good play. Given that SE probably isn't going to let a job go without a gauge mechanic at this point, this scenario is the best I can see for lilies. And I really hope that's where it goes rather Afflatus Cure 3 or nowhere.

Lack of interaction within the kit
Good examples of 'interaction' are 5.X WHM Plenary Indulgence and Temperance (which really should be an upgrade from Divine Seal) ... however perhaps the worst example is WHM lilies; they are essentially instant Cure II and instant Medica, so why do we need two extra buttons? It would feel better if lilies just made Cure / Cure II and Medica / Medica II instant cast, which would not only introduce some choice but free up buttons for something more interesting, like Aero 3? PvP Protect? Stoneskin? Cleric Stance? Divine Seal? an oGCD damage spell?.

Technically, keeping Afflatus skills as their own button is likely meant to be a choice enabler. The choice is "do I want to save this Afflatus skill for when I need to move or weave, or use it now for healing?" Leaving Cure 2 and Medica open lets you save the afflatus while still getting the specified type of heal out.

The issue with this is that there's not enough damage dealt to the party in this game to make this a valid choice within most fights. Many times you'll use a different ability entirely, or not heal at all, if you want to hang onto an afflatus skill. As such, unless encounter design changes, I don't think much would be lost by folding the buttons together as you propose. This kind of design strike-out reflects how poor the dev team's grasp of how healers actually play is.

That said, I have never understood the button bloat fears. 3 X-hotbars for controller on a W-bar setup or flipping between 2 main ones with a third for niche or long cd skills has worked perfectly for me. Trying to require every job to have fewer than 32 skills is unnecessarily restraining kit diversity imo. Definitely a fan of OG Fluid, PvP Protect, or a sub-50 Divine Seal returning.

Lack of general thought required
Due to the first two issues it feels like Healer gameplay has become very stale, just spam (your now limited) DPS until you need to use a healing cooldown (of which there is now an overabundance)... no thought, not much choice, no real ability to optimise, just play like you are a bot (and hope someone gets hit by something they shouldn't to break up the monotony) :/
And of course the new AST cards are the worst example of this, say what you will about the old cards but at least they required some thought.

In anything sub-Savage, this is 100% true. MSQ especially is dreadful on healer, because the damage output can't be anything that would kill the most fragile of DPS.