Dawntrail is already finished. There's no use asking for a change. There are two ways out:
1) Hope that the new foray content will replace all four-man content for tomes and relics. No healers should be required. You can't queue roulettes without a healer, so those forms of content will just have to die. Raids can be cleared with non-standard parties in PF as usual. No one will miss the absence of healers and the game will be better off without hallway dungeons, so nothing of value will be lost. Many MMOs and RPGs don't have a healer class either and you will likely enjoy forays more.
2) If #1 isn't possible, make The War Within more popular than Dawntrail. You all will have to go back to WoW where healers actually exist. If #1 is impossible it would likely be due to forays sucking or not even existing, which is typical for Square Enix. No forays would mean that Dawntrail would be worse than both Endwalker and WoW and you can safely leave the game without missing anything.
I'm sure a couple of people will be sad to see healers in FFXIV die off, but most people will be fine. It's a video game and healers were always trash in FFXIV. Don't pretend that Cleric Stance made anything better, because it didn't.
And if you really, really want to heal in a video game, may I suggest not letting a woman do a man's work?