Seen this way, rather than the walking band-aid which healers tend to be viewed as, makes it more obvious how the healer archetype just won't work in FFXIV no matter how much SE tries to rebuild them. At the very least, it clashes too hard with how older duties are designed, and there's no way SE has the resources to rebuild older content to this degree.

So we have to settle with an alternative. If SE doesn't want healers to do lots of damage nor spend a lot of time hitting DPS buttons, then there's only one solution: make healers into supports instead.

By replacing much of the redundant healing kit and simplifying that side to at most 8 buttons, there'll be plenty of space for buffs. AST already has a working buff system, it just needs the buffs to feel impactful rather than be slight bonuses that can be accounted for by normal damage variance. Make AST cards push the realm of 20%+ damage bonus for single targets with capstone abilities doing that much for the entire party, then the number of complaints for the cards will plummet. Though having only two effective cards is still a problem.

For WHM and SCH, if the buffs were set up like a DPS rotation, but done on an ally instead of an enemy, then SE'd have some quite happy healers I think. Players will be happy doing interesting and impactful stuff during downtime, all the while healing when necessary.

For example, WHM could have Cure, Cure 2, and Medica be their mainstay healing spells. Cure is weak but instant, but the other two have cast times but are powerful. Each one give one of three random resources. All three together can be used to give a big party wide buff, while each resource somehow interacts with the buff if used by a corresponding skill that consumes it. One could extend the buff, another could empower it, and the third could add a secondary buff. Of course, there'll have to be some management abilities to avoid being swamped with too many of one resource.

SCH could have only oGCD heals, and a GCD scan ability. Scan a target, and it produces an analysis resource. Get a certain number of analysis resources and you can convert them into a stratagem buff for the party. With the stratagem buff up, the SCH could use a tactical evaluation GCD on the buffed party members to gain tactical resources depending on the role that the ability was used on, which could be used to further improve the party buff like the WHM's buff.

This was only something I came up with in under an hour, yet would satisfy both SE and the players' desires to a reasonable degree I think without SE having to expend resources fixing old content.

Fundamentally though, healers need to change from a philosophical level. Healers only healing doesn't work with how FFXIV is designed, and as a result, healers spend most of their time pressing DPS buttons even in the hardest raid content, which gets worse as we improve our gear and people get better.