This has always been an issue, and I doubt it will ever change.
Players can easily recognize that something is wrong, even if you only have a surface level understanding of the gameplay. But trying to figure out the specifics of what feels "off" is a lot more difficult.
For me it absolutely is the gradual removal of small moment to moment decision making, XIV never had a huge amount of it but it was there.
Fluctuating resource generation, cooldowns not automatically aligning, smaller role/job mechanics that needed tracking, just to name a few.
Pretty much anything that wasn't just making sure to press your oGCDs on cooldown to keep them within raid buff windows, which is all we're doing nowadays really.
WoW on the other hand overdid it, especially in BfA when the azeryte armor gave you a bunch of procs on top of those from your spec/trinkets you already had to track, while making the actual core class gameplay simpler and simpler since WoD. It became more about juggling item procs than the fantasy of playing a mage, or a rogue.
Wall to wall is basically all we have in dungeons now, that is part of the issue. Sure, bring in some minigames, really anything other than 2 trash packs -> wall -> 2 trash packs and then fighting a single enemy in an arena that makes you dodge the same 3 or so AoE patterns.
Doesn't surprise me that a lot of people have kind of just gotten used to the fast food design of dungeons.
They've served you nothing but the exact same cheeseburger for years and now they suddenly give you a salad when you were expecting another cheeseburger.