Not all casual players, because it’s such a broad category. There are casual players who will log in and keep competitive with a specific game mode. If all you’re playing for is your IO score, you can do that as a casual player.
WoW isn’t a bad game for casual players, it’s just a bad game for a diverse audience. For specific types of players, it is obviously a great experience still. Perhaps a better one than it used to be.
The addition of M+ took a lot of people who weren’t logging in frequently, and gave them a reason to do so, if overcoming dungeons and difficulties with a group is your game. But the addition of M+ also created a second group of PVE players, on top of raiders (and not all, mind you, but enough), who loathe the concept of feeling driven to do any other form of content.
If there is a path to progression or any optimal way to get something that ties into a mechanic that could potentially increase your capabilities outside of the instanced content these people enjoy, there is outrage over it. People leave over it. And I don’t believe those people are the “hardcore” or “no life” players that are rebelling against value in the open world.
It’s likely the challenge/progression-driven casual players who have limited time to play, and they don’t want to feel like they’re gimped because they can’t commit to what they call “chores.”
It gets worse when these people decide they want to invest in alts. It’s why we don’t have a good leveling experience anymore, it’s why nothing you do in a patch matters anymore when the next patch drops, etc…
The game caters to these people. The challenge-driven casual instance player. And for the other casual players who aren’t challenge-driven and still want a solid RPG experience with a replay loop, we can’t have it unless they find a way to design something that doesn’t encroach on their enjoyment.
So that’s where we are right now. I play WoW for the questing, the new story bits, and the combat mechanics. I play different games for the better quality of the replay loop.