Start by taking MCH.
Add in Healer Role essentials.
Remove over-APM (healers need weave room for oGCD spells, similar argument to GNB needing room to weave defensive CDs)
Cast time spells:
Diagnosis
Prognosis
Raise
Esuna (if not combined with Diagnosis)
Pneuma
Instant cast spells
Eukrasia
Eukrasia Diagnosis
Eukrasia Prognosis
Instant cast Weaponskills
Dosis [D1]
Dosis 2 [D2]
Dosis 3 [D3]
(placeholder names)
Plegma
Dyskrasia
Toxicon
oGCDs
Healing:
Kardia
Pankardia
Durochole
Ixochole
Karachole
Panhamia
Rhizomata
Icarus
Soteria
Damage:
Gauss Round
(placeholder name)
Rotation:
Dosis -> Dosis 2 -> Dosis 3
This is your Heated Split, Slug, Clean Shot filler rotation. Trigger Kardia for some amount of healing. 300, 330, 360 damage (combo actions), the latter two do only 200 damage if not used as combo actions.
Plegma
This is basically your Chain Saw. AOE GCD with a CD. 20, 30, 40, 60 sec…not sure the best CD here. Maybe 2 charges, maybe not? And for the love of god, give it a 25y range.
Dyskrasia -> Toxicon
This is a 1-2 AOE combo (like Tanks have; I realize MCH doesn’t, but roll with it). 160 and 180 potency, Toxicon only does 100 if not used as a combo action. Note that the single target spells are instant cast now, so Toxicon isn’t needed for that. This is your Overpower/Mythril Tempest, etc standard 1-2 combo. Granted, a lot of DPS have a ONE button AOE “rotation”, but let’s go with it.
Pneuma
60 sec CD, this is Requiescat, for lack of a better way of doing it. It boosts the power of the next 5 weaponskills within 15 seconds. Roll with it. Does an AOE heal, but Zoe doesn’t exist anymore. Your one cast time attack, though you could Swiftcast it if necessary due to movement. This also opens your burst phase. Could be 120, but I personally feel anything I can’t press every 60 sec or less kinda sucks and doesn’t really justify existing as a button.
Gauss Round
oGCD weave attack with a relatively low potency (80? 100? Somewhere in there) and 30 sec CD. Using Pneuma and any abilities triggering the Pneuma effect (the 5 attacks within 15 sec after it) reduces the CD of Gauss Round by 15 sec. Sure, I’m ripping this straight form MCH. DEAL WITH IT.

Note this also would work with the AOE rotation since Pneuma doesn’t care if you’re doing single target or AOE. Maybe this should be an AOE attack that does the potency then 50% falloff to surrounding targets? I dunno, open to idea. Could have the buttons change to “Eukrasia ____” like how MCH used to change from regular shots to Heated shots, but…that’s probably unnecessary (and Eukrasia Dyskrasia might be confusing, as might these buttons NOT interacting with the Eukrasia button).
.
Filler Rotation is D1, D2, D3 on repeat, use Plegma on CD, then Pneuma on CD, squeeze in (ideally) two Plegmas then a D1/D2/D3 combo, completely with Gauss Rounds plugging away in between them. Remember: Doses have no cast times, so you can oGCD weave those Gauss Rounds and, if needed, heals.
AOE Rotation is the same thing, we’re just subbing in D1/2/3 for Dys/Tox combos.
.
Could have a “battery gauge” type thing, but I’m not sure how to work that in OR what to connect it to. Pneuma is basically Hypercharge + Wildfire here. Dosis combo average damage is equal to casting Dosis 3x today. Might have to adjust something up to make up for the missing DoT damage, since the DoT isn’t here.
Idea for Rhizomata: Grants one Addersgall; guarantees next ability used is a critical hit. Could be interesting for both healing and damage…but I feel like this would in practice just be used for damage. Reassemble with a nudge. CD 55 sec.
Pankardia is an AOE Kardia for 10 seconds on a 60 sec CD. Figure it out.
Hamia is removed. Panhamia now is a 60 second CD and only has 4 stacks. Figure it out. Maybe Hamia is low level and upgrades to Panhamia (reduce it’s effect to be Panhamia on a single target, the upgrade makes it AOE but keeps the same potency).
Holos doesn’t have a heal, just barrier and mitigation.
Raurochole removed. Krasis now has the additional effect of reducing damage taken by target by 10% for its 10s duration.
Physic I REALLY want to just remove.
Zoe removed most likely (you have Rhizo for basically this same thing now).
Pepsis…I have no idea. I want to remove it, but I also vaguely like it as an ability. Ugh…
Soteria has some wording that it only works on Kardion, NOT Pankardion, effects granted by you.
Kardia has a recast of 1.00 sec (or 0.00 sec, but not sure if the game code does that) allowing quick swapping between targets at any time.
Thought about doing some off the wall stuff, like an ability that has two Nouliths fly to a spot and radiate AOE healing but your damage and cast healing spells are cut in strength by 50%...but that’s probably a bit much.
I really want to do SOMETHING else with Eukrasia, but for the life of me, I can’t imagine what. Using it with CD spells means you’d just always use it on those spells (e.g. Reassemble on Chainsaw) and never cast the base spell. Maybe could do a “Ready” effect allowing a 1-2 thing, like Plegma-Eukrasia Plegma? I dunno. It just seems like such a neat idea for conserving hotbar space and making some cool thing, but then using it for that seems iffy. Like I could make Eukrasian D1-3s, but when would you use them/when would you NOT use them? Maybe they’re only ready after Pneuma, but then you have to deal with weaving all those Eukrasias AND Gauss Rounds AND any healing you need? That sounds like a terrible idea! I really REALLY would love to do more with it, but I can’t think of WHAT would be good and functional to do.
No DoTs, sorry. But look on the bright side, basically no cast times, too, which should make it way easier to drop few damage spells unless you have a strong need to GCD heal. It’s fine. If we’re really worried, we could do something about GCD heals reducing the CD on Gauss Round or Plegma or something somehow to even out the damage. I dunno, I’ll think about it some more later. This was just a quick idea slapped together to get a basic something I could play with mentally while I sleep anyway.
.
Granted, this is only 28 total buttons (including Role Actions)…so maybe I’d add a few more, I just think this is a good start and I’m not sure what good to add/leave in. Like I could leave Taurochole and Krasis and Zoe and Pepsis in, but…
Maybe this is a decent starting point.