Ty has outright said all Healers must be changed, not even one can remain. He also opposed the idea of adding a new healer with the current paradigm while changing the existing four so that a person who likes healing now could "shelter" under the new healer. (That discussion in particular went hairy because of confusion over it being a Class or a Job, since we know classes in FFXIV aren't full Jobs, but he seemed not to like the idea of there being a healer Job that might have an aesthetic he'd like to play that doesn't exist in the changed/more complex state).
Semi has also insisted that they must all be changed (or specifically that WHM can't be "left behind"), and frequently used the argument like Ty that we have to change them all to be complex since someone might like one aesthetic and would be upset if it was "the simple one" and they wanted the complex playstyle (completely disregarding that the people who prefer the simple play style would not have any option at all). Semi is...quite...vehement about this, so if she sees you suggesting it, you'll likely get an earful.
Shurrikhan has made a similar argument to the aesthetic one, too, most recently about Ranged physical, but when I tried to make the connection to Healer and infer that means we shouldn't change all of them, brushed me off. [EDIT to add applicable quote: Askellington and Rein_eon_Osborne have both said that not changing one of the healers would be a punishment to whichever was left unchanged, and refused to see that someone like me sees the change as the punishment, not the being left unchanged.
Roe has called it garbage design that shouldn't be allowed to stay. (As she says in her reply to you, she thinks her changes would be "roughly the same", but that's "the same in the sense of still being the easiest" not "the same as in not being changed". Kind of like saying giving WAR two DoTs would still be "the same" since it would still probably be the easiest tank; objectively, that's not the same, her "roughly" is a pretty big approximation.)
Sebezy is a bit more muted, but seems to also hold that they should all be changed, but doesn't engage in these discussions as much. Fulminating and Nizzi are kind of in this camp as well in they also seem to oppose leaving any healers the same. I think IDontPetLalas may be in this same group, I can't remember any specific time she made the above arguments instead, but she's been consistent in disagreeing with me when I bring things like this up, so I THINK she's opposed to it as well?
Regardless, I think it's been pretty consistent here that every time I've brought it up, I've been told we can't do that. Until today, with Deo and now you, I've never seen any other poster here support the idea, and I've been shot down/opposed whenever I propose it.
WHM and SGE. WHM because it starts at level 1, has a more or less similar playstyle to what it has for the game's entire history absent HW (even in ARR it was played much like today except for very top end 2nd Coils healing, as Sebezy can attest where it was pushed to the limit there and a lot more Cleric and damage was used), and is, as Misshapen Chair (a video I often link on this topic that makes this exact same point: https://youtu.be/sbWubxOTUWU?t=676
The other that would make sense to me would be SGE. While a BIT more complex, the thing it has going for it is it was introduced this way, meaning there's no "lost glory days" effect. That is, many WHMs want Aero 3 and possibly Cleric Stance back; some SGEs want SB DoTs or ARR DoTs back, or the old Eos where you could macro her abilities and such; most ASTs seem to want the old cards and hyper-oGCD stuff to weave and manipulate those like old Sleeve Draw, Royal Road, and Time Dilation. SGE is also the most DPS focused of the Healers right NOW, so there's an argument for SGE being the one to remain as it is. Btw, this is the one in particular Ty hates me mentioning; not to keep mentioning him, but SGE is his favorite of the archetypes, and he points out - rightly, I think - that SGE's lore supports the idea of a more complex healer, both in how controlling nouliths is described as very challenging to master and that unlike the other "give you healing aether" WHM/SCH or "turn back the clock/fate and rewind a bit of time to before you were wounded" AST, SGE is a doctor, their lore describing them being knowledgeable of both magic AND Human anatomy. Meaning they are using a much more technical form of healing, and their nouliths (an advancement from ancient aether-infused rocks that were used as early magic wands) are delivering healing precisely to where the wounds are in the precise way to heal them.
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In any case, I've posted this a number of times, and am kinda shocked seeing two people in one day seemingly on board with what I've been arguing for months.
This. Though "some" means "all that weren't started by Ren", as I've thus far been the only person here to seriously propose and champion the "4 Healers Model" idea.
The "some of which" referred to in favor of leaving one alone were all me, I believe. Originally, it was leave 2 alone - one each of Pure and Barrier, with my proposals being WHM and SGE or WHM and SCH (there is something to be said for SCH/SMN being "entry" Jobs on one class for people that are turbo-casuals to have both together as opposed to one being super simple and the other being super complex). I eventually trimmed this down (the word "compromise" comes to mind) to just one. ANY one. I even said once AST could be the one to not change if that was allowed, the one Healer Job currently that I don't like and don't play. That I would change to that one if even just it could be left alone. I was willing to give up the three I play (AST is the one I don't) for one to stay the same, thinking that 25% staying the same and 75% changing was more than fair...and was told to go pound sand. I even made a proposal for SCH for a relatively minor set of changes that would add a bit of rotational complexity while "paying that off" by easing some of the Job's clunk - which doesn't meet the "1 left alone" standard, even.
That last one is the only one that was at all semi-well received (not universal praise, but not universal condemnation) here, though it was not because it was "leave 1 alone" so much as it was "change even this one, and make changes that include another DoT and DPS rotation optimization", so even that doesn't meet the idea.
So until today with you and Deo both, there has been no agreement with "leave 1 alone" in your case and "leave 2 alone" in Deo's.