I agree with most of the sentiments expressed in both the OP and this thread in general.
That said, I'll hop on a soapbox as a (former) evil mustache-twirling WHM enthusiast, whose only goal in this veil of tears is the sweet delicious suffering of AST and SCH mains. (I kid, I kid)

There are a lot of things I've wanted for several expansions now. Much of it boils down to Balance and Fun.

Balance:
Based on the usual direction of the endless maelstrom of discussion over what exactly "balance" means on these forums, I feel I need to explain what *I* mean by balance, and I'll have to jump back to the last two expansions to do it. No, I don't mean total DPS numbers need to be within X% of one another or all is lost. No, I don't mean that the world is coming to an end if my class doesn't get this or that skill. No, I don't think being whatever percentage below the meta speed pick makes a class broken and unviable, never to darken a party slot again. What I mean by balance is that I don't want the straight return to the healing world of late Heavensward or Stormblood I've seen several people around the forums suggest. Perhaps it's a mite unfair if you have three jobs in a role, and two of those jobs have strong personal damage, powerful healing, mega shields for any occasion, breezy mobility, infinite MP, a Batman toolbelt of buffs, and a variety of debuffs, while the third has like...maaaaybe half that list on a good patch, with notably fewer spells to boot. Heck, I'm not even saying jobs shouldn't have all of those cool things (though having explicit weaknesses can be fun too!), just that there's something that smells funky when your job has enormous holes in its list of capabilities, and that list of holes is much smaller on other members in your role, without commensurate weaknesses to compensate.

I can't speak for others here, but that's what I mean when I say the healer role was "unbalanced" in the past. Not that WHM wasn't in the speed meta. When my job has almost no unique capabilities. When my kit overlaps with the other two, and they're still pretty competitive in those areas or even outshine what I'm capable of, making that lack of uniqueness even more stark. When the other two have not just extra spells, but entire CATEGORIES of abilities that I don't, on top of being pretty great at basically all the things that I do. All three of those things came together and turned me into a chronic forum complainer since late-Heavensward. It really highlighted for me then (and ever since) that WHM's tools don't really do much outside increase health and do direct damage. In a series with so much inspiration to draw from that it makes one's head spin to think of all the possible things a designer could stem creativity from. I'm not making a statement about any single issue; the list is only elevated from "annoying" to "problem" when the items occur together. I'm Mad On The Internet that White Mage has been painted into this stupid corner where it's not allowed to have practically ANY meaningful gameplay loop outside Simplistic Ally Health Up Button and Vanilla Enemy Health Down Button because **reasons**. Of COURSE something's going to crop up when this weird design restriction applies to only one of several job choices.

Fun:
People have different definitions. I finally threw my staff in a woodchipper because I was done with it. I want an expansion where I look forward to an exciting list of changes. Not one where I'm bracing for the massive laundry list of abilities they're snatching away from me to clear the road for it. Could they maybe please, please stop nerfing Holy? Stop inventing new and creative ways to slowly grind Fluid Aura down into a functionless emote? Making downtime duller and duller with each expansion? Taking old abilities away, reducing their potency, and reskinning them as "new"? Shuffling abilities off into role skills? Job lore that hints at a mysterious civilization past, but in practice is often "Someone has reported a stinky patch of ground. Clean it!" I'm not even talking on a class balance level or comparing battle scars with AST or SCH with this whinge. It doesn't feel good as a player when over time your job's list of uncalled-for potency reductions and skill slashes grows longer than the list of changes you find fun. White Mage is literally the only job in this entire game for which I've seen multiple serious suggestions that it "remain" a casual job. That Netflix-'n-Snooze Mage is the natural order. The Sylphies need a haven with an ankle-height skill ceiling that "should" be as close to a limited job as possible, pruned down to little more than Cure, Medica, and Glare (and Glare is a topic of fierce debate for the next prune, because doing damage ruins the Fairy Princess Healer dream). I exaggerate there, but it's a sentiment that gets me fired up every time I see it. I have no interest in the job aesthetic of Scholar or Astrologian. Can it maybe, in some timeline, be possible that all THREE healers have interesting stuff to do, with their own niches, with their own choices to make, with their own different ways of filling their downtime? I'm talking something that feels good and impactful, not yet more busywork like "lol let's mash the Medica button over and over and over and over again because that's not like Glare spam at all". A suggestion like "we should keep {insert DPS class here} dull because we need a braindead simple damage dealer that mashes 2 buttons for 90% of an encounter to appeal to all tastes" would be laughed out of the room. I quit this role not just because I was disappointed with Shadowbringers' treatment of healers, but because it's been made clear to me patch after patch, expansion after expansion that my favorite flavor of job is not the premiere Dumdum Healer for Beginners by accident; that (Regen Aero Stone Stone Stone Stone Stone Stone Stone Stone Stone Aero Tetra Stone Stone...) is the GOAL. The job designers are so out of touch with how healing works in their own game that this dreadful gameplay loop is what they've got for us.

Here, have this (somewhat) simplified script:
If tank doesn't have regen, use regen
If one person's health goes down below comfort zone, counter it with one of several functionally identical One Person Health Up spells, in a relatively static cooldown priority order.
If 3+ people's health go down below comfort zone, restore it with one of several functionally identical All People Health Up Spells, in a relatively static cooldown priority order.
If multiple enemies exist, stand in them and Holy
If one enemy exists and they don't have (WHM Bot DoT), (DoT) them
(Generic WHM spam spell) closest thing

What I see is a decision "tree" that is a straight line. Would YOU, faceless reader, have fun playing Semirhagebot for six years? Because the engagement wore thin for me. I'll admit that my personal burnout with this no-growth-allowed job was a strong factor in my decision to quit healing. And simply returning to the glory days of AST and SCH dominance wouldn't create many more lines in Semirhagebot's code.

I don't say this next bit to minimize the things that Astro and Scholar enthusiasts have strong reason to be angry about or turn these design decisions around make it "all about me", but from one perspective? Squeenix is -so bloody dedicated- to making sure White Mage has no niche, no identity, no further entertainment to offer outside of spamming simplistic spells with little to no synergy or skill cap that they would rather throw out what fun design they had in the other two healers than give WHM an actual complete kit. Afflatus Misery was too little too late for me. The "WHM can stay the boring healer, that's its identity!" crowd can bite me.

If you love the current iteration of White Mage, good for you. My poor 1 key begged for its life after job changes were announced.