How many times is this question going to be asked and the responses ignored?
The problem with the current gameplay implementation is that significant portions of many fights don't require active healing; whether that lines up with the director's personal philosophy or subjective playstyle on what he wishes was the case is irrelevant here when we're talking about the actual implementation. As such, since it's inefficient to only heal papercuts or outright stand around while doing nothing at all, your only other way to really contribute meaningfully to the fight is to add toward total damage during those downtime periods, and the director himself has noted that said periods get longer in length as gear levels increase; this is something that he's gone on record as being aware of but hasn't been able to fix it with his personal ideas alone.
And if said attack contributions are extremely limited and repetitive in comparison to other jobs in the games, to such a boring degree that it's actually rather insulting to the player's intelligence, then that's a major problem that shouldn't be completely ignored. Limiting DPS action variety does not limit the amount of total downtime for healers.
Also, even if the developers were somehow able to improve healing checks for all content across the entire set of base game and past expansion instances as well, always forcing minimum item level requirements and managing to redesign all older fights on an individual basis, that fundamentally will never be able to fully address repetition within single-player content such as Main Scenario quests; healers either need to avoid playing as their role in order to have fun with said content, or they have to remain bored because of some irrational fear that a small number of level 80 (soon to be level 90) healers have that adding a few more optional DPS actions will somehow cause them to completely shut down and refuse to practice optimization despite being at max level.
Forgive me if I sound annoyed at this point, but I've been repeating myself a lot lately.