Has anyone quit healing?

[YusiKha]

2): The developers have stated as recently as last year (if not even more recently) that they do not take Healer DPS into account regarding endgame fights. This is likely the cause for actual healer play being so unsatisfying for a large amount of the playerbase (spamming a single dot + single nuke or a single AoE button for a disturbingly large amount of content in between oGCDs).

This is only true when people are overgearing the fight.
If you're trying to tackle the content in the appropriate crafted/normal raid gear (ie 450 for E1-4S), you 100% need healer DPS.
Here is a week1 E4S kill log. (Percentiles are based on current clears, so ignore them) The healers are contributing 13% of damage, and the enrage would be impossible to beat without them.

Maybe something like WoW Smite Priest or MW Monk in that their basic damaging spells also automatically heal nearby allies, or increases rDPS? Maybe mix in some of their more unique abilities as well when the base kit is there.

That'd be more a thing for a new healer (maybe not damage itself contributing to healing, but rather the damage GCDs filling a gauge that could be spent to heal).
Current healers' oGCD skills take the design space of concurrent healing.