I've been doing this thing where I take job XYZ and systematically queue for, in order, every single dungeon, trial, and raid, just so that I know that I've done them all at least once on that job. (To be clear, only the trials and raids that are typically done through Duty Finder on NA/Crystal.)
At the moment, I'm in the middle of post-ARR on WHM, and I have to say: It's actually kinda fun. It's actually keeping me engaged. Nevermind the fact that WHM's Lv.50 kit is... well, WHM's Lv.50 kit. None of the tanks are self-sustaining and immortal. The trash and environment tack on debuffs that actually hurt. There are janky dungeon-specific mechanics that no one remembers.
I feel like I'm a better, more awake, more in-tune healer in this content than I am in, say, any Lv.90 trial or raid.
So, to bring this back to healer "rotations": The game needs to do something to keep me awake. If you think I'm a bad healer in Lv.90 content because I keep DPS'ing... It's because I fell asleep pressing 111111112111111. It's because I assumed, "who's actually gonna fail this mechanic and take damage?"