This is just silly. That's not their proposal at all. The question at hand is that in most content (I'd say almost all the content, I think week 1 HH on P10S and p1 and p6 in TOP are the only instances of significant healing output required in the last year and a half) the requirements for healing are negligible. There are many ways to address that problem- you could either simply increase the requirements for healing output, or design mechanics that cater specifically to the current healer kits (like fights with random prey markers between raid-wide aoes that require spot healing and healer attentiveness- and I mean truly random here, not 90s into the fight, maybe 30, maybe 45, maybe 60s...).
On the other hand, when healing output isn't required- which, right now, is almost always- healer players would like to have some sort of depth or "business" in their damage rotation to keep them entertained. I'm not sure if you played in those times, but in Midas Savage, when it first hit (and when I still player healer), this was an actual decision I had to make. I'd sometimes let some of my dots fall off (even though I knew I had to refresh them) because there was a wave of incoming damage that I had to take care off first (specifically thinking of A6S here). This kind of depth is gone.
I think simply bringing back Miasma II and Aero III with different timers from Dia would be a small but significant step towards ameliorating this issue. I've played a bit of healer in patches 6.4 and 6.5 and I agree with a lot of the sentiments here- I almost forget Liturgy exists because it's completely unnecessary. Heck I overheal sometimes just using the lilies to get Misery for burst...
I'm honestly confused about this hostility towards healers. You make a sweeping statement about the healer playerbase, but I've had issues with tanks just as often (including aggro issues, which is just silly in EW) and dps not even being able to do a simple 1-2-3. Tanks often lament the homogenization of their role, and I agree fully with the sentiment. These complaints have a lot of merit to them, and after 6 years, it's unsurprising that people will mobilize to show their discontentment. Just because you don't share their opinion doesn't mean you (and others like you) should come here to show gratuitous hostility.