Any more clarification on your story? Did it actually happen or are you pulling hypotheticals here? A simple button press of Medica II would have been enough to get you through any 'easy boss' and it's unavoidable AoEs. In your case, assuming you weren't also eating avoidable damage (Dead End Peacekeeper's No Future is a family favourite for people eating multiple AoEs for example) then it's pretty clear to say that that healer was either A) not paying attention or B) just had no grasp of their kit to the extent that they just couldn't react in time. Let's break these down a little.
In the case of A) where the healer just wasn't paying attention, do we not think that making healer gameplay a little less tedious would give more healers more reason to actually pay attention rather than zone out on whatever video is playing on their second screen? I'm not going to lie, I find it hard to stay focused on the duty if it's dragging on and I'll routinely start doing something else on the side when I can get away with it (which is now possible in just about everything outside of Savage progression and Ultimate).
As for B) where the healer just didn't have the skills and knowledge to understand what to press in this situation. I've said it a few times now but I'll say it again. Why is our portion of the game being tuned around these sort of people? It doesn't matter what SE do and how brain dead or easy they make things. These sorts of players will still fail. It's common to see healers in 24 man that struggle to barely 6 CPM. That's a single button press every 10 seconds! They will fail no matter what SE do and frankly, in content where these sorts of players will be comfortable at, that's absolutely fine as it rarely causes much of an issue in the grand scheme of things.
TLDR: Adding more engaging mechanics to healers downtime isn't going to make a blind bit of difference to this sort of player because they don't use their kit as it is. Why are they going to suddenly pay any attention to this sort of addition if they can't even understand how powerful abilities like Assize and Earthy Star are?
At the risk of coming across rather sharp. I'm of the simple opinion that your objection is entirely built on the grounds that you expect us to carry you and nothing else. Anything that gets in the way of us spamming cures on you is a bad thing apparently, our enjoyment of the game be damned.
Sad TBH.
