There's a CD you can take on Druids in WOW, a 90s CD that makes the next 30s of singletarget damage also copy 20% of the damage done as healing to a nearby ally. Except for Resto Druid, the healer spec, where it works in opposite: Healing dealt is converted to damage on a nearby enemy. And because Druid's healing style is to place many many different HOTs on everyone, it results on many many chips of damage being echoed onto a nearby enemy. We could have a CD that works as simply as 'when you deal single target healing, 50% of the healing is also dealt as damage in an AOE around the heal target'. A 'totem' of sorts like that Genshin one would work too, but I'd rather see that as a whole seperate job, that has many totems with different effects
(trimmed cos it's so bloody long)
I'm going to be very honest. If someone is doing the 'hardest content in the game', they are expected to know how to play their class. If their class changes and becomes 'more complex' for whatever reason, they adapt. If they're doing Savage, they have the skill to adapt to rotation changes. We do it every expansion on any non-healer, because they get new DPS skills to use. You are arguing that there is not just one, but many, enough to cause a sizeable enough dent in SE's pocket, players who are simultaneously skilled enough to be doing Savage (and at a speed that means they can't just trivialize the enrages with more gear), and somehow at the same time, are completely incapable of learning how to juggle a second DOT. That if we change all four healers to have more DPS actions in their rotation, this massive chunk of hypothetical players will have no class to play, and just quit, rather than stepping up to the challenge and improving in terms of skill. It's insane to even imply.
If someone's pushing Savage/Extreme early enough that 'not using stuff beyond Glare spam is causing party to hit enrage', they're competent enough to press buttons beyond just Glare spam. If your hypothetical player who can clear Savage but also not use a second DOT existed (pretty sure they don't), I sure as heck wouldn't play with them in Savage. If Bio AND Miasma is too much for them to handle, how can the party trust them to do Devour right? Or High Concept? I wouldn't even trust them to handle the 'braindead' P7S markers, and that's.. well, braindead, its in the name. Besides, there's a world of difference between different pieces of high end content, both in terms of timing and level. Week 1 P5S has a tighter check than week 20 because of gear difference. But even then you can afford mistakes, because it's tuned for i600, and everyone's running i610 crafted gear. Week 5 P8S is harder check than week 5 P6S, because it's a later fight in the tier. So, again, if the hypothetical player runs into a situation where they can't just Glarespam their way through, they have choices, learn how to play their class properly (shock and horror) or wait till gear lets them bruteforce their way through. And again, if they are at ie, week 3 P8S, they're already competent enough to execute more complex rotations, even as a healer. I don't see why 'the player should be allowed to Glarespam to victory in content, and if they cannot, the content is what should change, not the players approach'. We already have issues with how steep the learning curve goes from story content>Extremes>Savage
Lastly, please remove your head from your backside before you suffocate, dying IRL would negatively affect your HPS output. You're almost sounding like FireMage with that last line