How to fix the healer problem.

[Doragan]

-Remove healer attacks completely. If you want damage, give them more abilities that buff other people

There's no way that could work in the context of this game. You still need to do a base amount of damage to complete MSQ, PoTD and Variant dungeons, overworld content etc etc.
On top of that, there's also the issue of having the entirety of a role depending on rDPS and having your own personal contribution entirely dependent on somebody else. If they die or something goes wrong with them, you are completely unable to contribute -- robbing you entirely of your player agency. Even past and current buffing jobs weren't as punishing.
I think the rock bottom the devteam is willing to go through will be shadowbringers healer kits. Anything below, and you run at risk of having healers not being able to clear past content, and realistically, I don't think they will properly remake the past 10 years worth of content to fit that design philosophy. They had the opportunity to do so too while redoing ARR and most of the past dungeons encounters, but that is clearly not happening.
Not to mention them removing protect entirely in Shadowbringers.

-Bosses will now do random, unpredictable attacks of different types against random players, that require the healers to react. Not reacting fast enough=punishment

We kinda used to have that with aa crits, but I think that stopped being a thing in Stormblood? Kind of a shame, but even then, we had cds to circumvent that entirely.