Sweeping generalisations are bad pls.
I was about the biggest Sylphie you could imagine especially back during HW. If it was my choice, healing would be far more frantic than it is now, random cleaves, splash damage, damage shields etc. I want to be pushed, but FFXIV's healing just doesn't do it, it hasn't for years now.
I think the biggest mistake you're making here is to assume that our DPS complexity is the only thing we've lost over the years when the reality is that you couldn't be further from the truth with that.
We've lost our buffing busy work, go back to ARR and you'd see SCHs merrily weaving Selene's buffs even if the reality was that they were less impactful than simply keeping Eos out for Whispering Dawn so you could Ruin more. Not to mention shielding required much more precision than it does today with slow casting shields being required on bosses that would merrily auto them off right before a rapid tank buster. AST is the best exception here of course, but even it's buff kit is a far cry from the mini game it used to be.
We've also entirely lost our debuffing kit. Remember when Virus chains were a thing? Eye for an Eye?
Lastly, resource management just isn't a thing anymore, MP for healers is pretty much a 'don't spam medica II' gauge coupled with some way to keep in combat raises somewhat under control in anything that doesn't enrage. A large part of that is down to us being able to offload so much of our healing on free oGCDs (E12S pt1 was pretty taxing on MP because the AoEs were frequent enough to actually start requiring GCD heals at times) but it's also far too quick to recover MP back as a healer as well. By comparison, a geared up dead Cleric in EQ1 could be out of the picture for 10+ minutes without Modrods.
The core problem is that once you've memorised the dance, there's very little to actually focus on as a healer between key mechanics. I want to have to pay attention, not find myself drifting off towards the second screen. At this point I'm far beyond caring how SE actually achieve this, just that they actually make an effort to give me something to do that isn't mindlessly mashing the same button.