Putting the tank rotations like that just solidifies the fact that you don't need anything complex to make downtime engaging. I don't see how updating the filler phase for healer is useless, I mean there was an entire healer shortage this tier because veterans got bored of Glarespam & getting blamed for mitigation issues and new healers didn't know how to keep up with P8S. Also, I don't see the appeal of Phlegma as an offensive ability, it's just a heal GCD that refunds the damage you could've done spamming Dosis. Same with Misery. Not that they aren't interesting abilities, but they aren't something you're able to constantly push in a rotation. And what do you mean with more options to shine in burst phase? 3 out of 4 healers already have 2 minute buffs. There's not much thought with pressing them.
This is my issue in general, what exactly do you like about 1 nuke 1 DoT gameplay? Do you like it because it's fun, or because it's easy? It purposefully uses no brain cells so you can spend more time healing, but... we aren't spending more time healing. That's the nature of the predictable incoming damage in ShB/EW fights. Maybe the only exception to the rule is Barb EX but even that gets invalidated as item level increases over time.
When I first joined in ShB when the free trial was updated, healing wasn't immediately easy for me. It was challenging learning to DPS and keep the tank's health up in dungeons. I was hardly doing damage and I still managed to let the tank die sometimes. But I *liked* that challenge. I felt myself improving and getting better at it up until the final patch of ShB. I feel like I hit the skill ceiling way too quickly. It was really soul crushing when I saw the EW job trailer and the only new thing SCH got was “run fast”.
Having a filler rotation on top of having to heal the party makes healers more challenging. The only opposition against this I can see is "I don't want healers to be hard", which is quite disappointing to me.