Part of the issue with any discussion of healer complexity is fundamentally just the massive disconnect between the high-end players, the low-end players, and the average players. Each group has *wildly* different needs (doubly so for controller vs keyboard & mouse on top of skill difference) and the game needs to be balanced so that the game is playable for as many players as possible.

High-end players want more complexity, more responsibility. The low-end players need to be able to clear MSQ content, normal raids, and alliance raids with trusts or randoms without much hardship. Those of average skill might want a bit more complexity, but also more in the way of options for "oh FUCK" options in the event of a fuck-up. Players on keyboard & mouse generally are okay with having more buttons than players on controller would be, while players on controller are okay with fewer buttons than KB&M players would want. Ultimately, CBU3 balances jobs so that they're playable for the most people in the most content, at the cost of being less tuned for any individual group.

The "obvious" solution would be to utilize the job system to its fullest advantage here - we have four healers, it's not unreasonable to aim them at different skill levels, but then comes the issue of, if Healer A does healing and DPSing just as well as Healer B but with way less difficulty, why would anyone play Healer B? Not to mention, CBU3 really doesn't want to lock anyone out of any story content - DSR having as deep a narrative as it does is frankly shocking to me, and honestly I'm surprised they never made a Dragonsong Reprise (Normal) to appease those who got annoyed at a plotline being locked behind an ultimate - so having any job or any role be difficult enough that a low-end player won't be able to see its job/role quest or do the MSQ with that job is basically out of the question. It'd also be kind of a problem to make such a change now, because there are low-end and average skill players who only really play healers, and if you suddenly ramp up the complexity of a job where these players will be below the skill floor, you've essentially told them "go level another job and hope we don't change that."

I don't envy the position CBU3 is in. There's not really a good solution here to make everyone happy, but when you're developing a big MMO that's also aimed at a crowd that doesn't typically play MMOs, you're kinda stuck between a rock and a fandom place.