I'm not personally concerned with DPS classes and how they play. I play healers. And healing is definitely not better now than it used to be. I used to feel much more engaged in the game when I had to make decisions about how best to use my mana. We're nearing "just press this one button and people will live" territory, although we're not quite there yet thankfully.
I just don't know how making it more braindead is considered improvement unless your goal is to expend as little effort as possible and reap the rewards.
This is very much where I'm headed to. Back in TBC, planning fights from a healer perspective, figuring out which RANK of each spell to use to stretch your mana out just that little bit further so you're not wasting it with overhealing since it actually mattered, playing with the five second rule to also get the most out of it(as a healer making sure I had max first aid so I could heal myself without using mana so I can regen faster), all of these techniques were pretty much extinguished after that expansion. There are still some healers that are complex, but I find myself needing to switch classes more often to get it(monk first introduced and being a melee healer, while making use out of both melee abilities and normal healer abilities to get the most out of the healer).
With Legion, it seems that Discipline priests fill that role now, so I can't wait to see if it's as fun as it could be. Still though, the game's direction it's been moving in usually haven't been positive(not sure still if removing the idea of buffs like Fort or Blessings is an overall positive to the game as a whole).