The only thing I see here, is people complaining about the game suddenly requiring you to think ahead. You won't have problems with cooldowns, if you don't overheal and if you simply just plan ahead and learn the mechanics.
Personally I have no issues with people facetanking everything in any dungeon, that I run on my healers. If I don't use any CD's of my heals before bosses do mechanics, and simply just insta heal as soon as the mechanic has taken their hp, then it's no issue at all. A great example would be RKE where you can easily predict whenever he's doing to do back stun, pizza mechanics or S-bomb. If you just save your heals for those, you have no issues healing up. Another example is RMH last boss, just know that people are facetanking in-out, back tail hit, the swipe after her scythe is in the air and so on, everything is good.
It really isn't rocket science, people facetanking mechanics that don't one-shot, is simply just you who has to step up and learn the mechanics ahead of time and healing accordingly.
Personally I run with Missy all the time, and I don't see her having any issues at all outhealing mechanics, even though I facetank like a maniac. This is all the while, while having top tier uptimes on her buffs, so don't complain. It's easily possible to do your job, even though people are facetanking all the mechanics that don't one-shot. It's only a question of knowing the fight and knowing the mechanics. You simply just need to put a little effort into the game, that's all.
Stop complaining and improve yourself, before blaming the game for being the issue.
Also before I get bantered for "But I don't have gear to facetank meteors bla bla bla", then just tell that to people before starting the run. No one will blame you for that. But don't complain that you can't outheal smth that's not a one-shot 'cause you can.