This is why I play Paladin I can feel semi supportive without the 1 button rotation
Dungeon runs without healers (or when 2 DPS is alive and im keeping em alive as tank, that's actually pretty fun to me) can actually be a lot of fun and choice making with that playing healer doesn't give me, even if something goes wrong i have so much resources alone, if it's a WAR/PLD or even a GNB they can already handle themselves and likely another player

My main issues with healers in general is more or less the one button rotation and never really the choice to actually use any of your damage loss healing spells, healers to me are just slight resource management without rotation

It's likely different on harder fights, but at the same time people did kind of clear without any healers, just PLD's, wars and a lot of dps with healing/boosting healing abilities. Which I don't think it's a issue with those jobs, its a issue with healers actual gcd heals never being needed, it's a issue with a lack of outgoing damage.

I think one healer runs are at least somewhat acceptable? especially if you have a lot of support based jobs to cover that weakness, but none? that's pretty wild. I'm just saying this mainly from a casual healer perspective, I've done a few savage runs and EXTs (nothing really recent either) as tank I'm not exactly a expert on fight design, but healers should feel important for all types of content at least.