I completely Agree with your take on Healers. The role of a Healer in MMO is that of a specialist Job that under normal circumstances, is more difficult to play than the rest because of the Healing responsibility and the impact any error could make, that's why in most MMO's, encountering a Skilled Healer usually had quite the impact performancewise when you compared it to a new player or other Classes that have a rather basic Healingkit on the side that just barely keeps themselves alive at some point.
But as for your suggestion on to return to the way it was before, i do have to disagree here, while healing itself was, compared to now way better in every way, i'd say it was okay at best in terms of gameplay. If Healers were to be reworked in a way it feels rewarding to play, they would need a rework from the ground up. I mean, just look at how FFXI designed their Scholar and White Mage for example (if youre too wary about the Links, just google them instead, it shouldn't be too hard to find them, especially since they're pretty much the first Link shown):
https://ffxiclopedia.fandom.com/wiki/Scholar
https://ffxiclopedia.fandom.com/wiki/White_Mage
For references sake, here are also some examples on how some other MMO's designed their Healers (the games i've mentioned are only one's i had positive experience playing at some point, so the choice might be a bit biased), try to compare those with the Skillkit we got for our Healers and you start noticing some things:
Tera Online:
https://tera.fandom.com/wiki/Priest_skills
https://tera.fandom.com/wiki/Mystic_skills
World of Warcraft:
https://wow.gamepedia.com/Priest_abilities
https://wow.gamepedia.com/Druid_abilities (Druid is a jack of all trades, that can specialize himself into being either dps,tank or healer)
https://wow.gamepedia.com/Shaman_abilities (Shaman is a similar take like druid, but instead has a melee dps, ranged dps and healer specialisation)
Rappelz Online (a old MMO that is currently more or less a walking corpse of a game in its current state, to put it mildly, but it is interesting for comparing reasons since it launched in 2006 where MMO's used to be somewhat...different). Reading into this might be a bit more of a chore because Jobs could branch off, instead of posting the Link for every Healer, ill post the Link that lists all Jobs at once (including their skills).
https://rappelz.fandom.com/wiki/Jobs