No, this game is just fucking old. That's what is going on. No matter how much new stuff blizzard is going to introduce people will bitch about it. Because in the end it will feel the same.
The only thing that felt different was M+.
Island expeditions? -> solo scenarios with random mobs.
Warfronts -> raids with 1 boss in open world with stages, a bit of grind and no challenge whatsoever
Artifact -> just some gear piece that grows in power.
Raids -> same as always
Dungeons -> same as always
PvP -> literally nothing has changed (doesn't matter if they removed pvp vendors etc. it stil feels the same, maybe except you can't remove players within 2 global cooldowns anymore)
And people fail to realize a simple fact: It's not expansion quality what makes them less engaged, its WoW being old and getting stale.