An idea about how to solve some of the healing problems

[Sebazy]

Honestly, at least as far as boss damage goes, it doesn't even need to be this complex.

Simply spicing up auto attacks on bosses would be a great start. Go back to ARR and Coil bosses would routinely have insta cast mini tank busters, cleaves and so forth that they would rotate alongside the proper big abilities. What happened to all of that?

Kaliya at min ilvl is a superb example of what a bosses melee should be like IMHO. Both tanks should be getting curb stomped all whilst the mechanics are going off around them.

The current obsession with comically long cast times with maybe a single auto attack between them has to take some of the blame here.

[NobleWinter]

It's been mentioned many times before that avoidable damage should punish people with damage down debuffs instead of vulnerability debuffs. Healers shouldn't have to work harder to heal because other people are bad. The group as a whole would have to carry the DPS output though. I do think healers across the board should get buffs specifically for GCD healing and things like Esuna. Let's say you cast Cure 2. You're next Glare should be worth twice the potency now. So Two Glares would be the same as Cure 2 and then one Glare. It's such a simple concept to make healers have GCD spells that are worth using by refunding the damage lost. That alone would go far to make healing more enjoyable if you knew helping people wasn't a sure way to hit enrage. Then lots of avoidable damage would feed into good healer gameplay.

[Grimoire-M]

It's been mentioned many times before that avoidable damage should punish people with damage down debuffs instead of vulnerability debuffs. Healers shouldn't have to work harder to heal because other people are bad. The group as a whole would have to carry the DPS output though. I do think healers across the board should get buffs specifically for GCD healing and things like Esuna. Let's say you cast Cure 2. You're next Glare should be worth twice the potency now. So Two Glares would be the same as Cure 2 and then one Glare. It's such a simple concept to make healers have GCD spells that are worth using by refunding the damage lost. That alone would go far to make healing more enjoyable if you knew helping people wasn't a sure way to hit enrage. Then lots of avoidable damage would feed into good healer gameplay.

I do want to acknowledge a potential alternative that doesn't make sense without a little context, but: Max HP down debuffs (iirc Suppuration is what it's called?) would also work to a limited degree. The main thing is they don't affect raw healing throughput in any way, but they do affect mitigation. Needing extra mitigation to deal with Vulnerability stacks is a common thing, but that's only if you're getting oneshot. Vulnerability (and Infirmity, for that matter) also requires you to pay attention to sustained damage sources (I know there's not many, but not every avoidable mechanic applies Vulnerability either), whereas HP Down doesn't (unless you took so many you're getting oneshot by things you're clearly not supposed to. Something that Tanks will screw up too). And given non-healer roles have a surprising amount of surplus in this area, they can help save themselves. The difference between that and raw healing is some healers (Mostly WHM, if we're being honest) don't have the tools to mitigate everything, so this puts the load specifically on non-healers in certain compositions, or at least keeps Shields relevant.

Having that be the penalty instead of damage could be an option in some cases, such as P2S's acidic water. I don't mind P2S's water as is, but some rando eating a DoT feels like far more work than having to baby them extra at a specific raidwide window. Vulnerability ranges in-between and sometimes on one of those extremes and that's cause it depends a lot more on the context of the fight.