You're attaching unsubstantiated value to a kind of "diversity" that flies in the face of mechanical demands; you neither prove that this actually HAS value (especially value that trumps just being able to handle the mechanics), nor do you prove HOW this could even be done, since it historically wasn't done in the past either (some things just sucked back in the day, like Fire Mage in Molten Core or whatever).
But at WHAT COST. Of course it's to just throw self-evident shit out there. "Everyone wants the game to be good!" Yeah, thanks for the insight, you have shown us that not many people want things to actively suck, that is a real revelation I must say.
THIS DOESN'T JUST HAPPEN IN A VACUUM. You don't just flip a switch that goes "fun class fantasy ON!", and neither can you just go "mythic raiding OFF fun class fantasy ON = it's what most people want" because those are not simple binaries, nor are they actually in any sort of simplistic antagonistic relationship.
As I said initially, the shift away from fantasy IN FAVOR OF mechanical viability happened way before M+ or mythic raids were as much as a fart in their creators' bowels. And do you know why that happened? Because 'most people' actually DIDN'T want to TRADE fun class fantasy for bad mechanics. It was more important to them to have a good time playing than it was for things to play super into the class fantasy. Now, again: this wasn't a simple binary, and we didn't just go from 100-0 to 0-100. These are just degrees. But it's fallacious and grossly ignorant to assert or even suggest that mythic raiding is somehow to blame here, or that you can simply tell what "most people" want AND WHAT THEY'RE WILLING TO GIVE UP FOR IT. That last part being the actual important part, if you want to state anything more than a vapid truism.
Prove it. You're throwing out all sorts of wild accusations that repeat some Wowhead comment's inane ranting, but this is FAR from easily shown or obvious.
Which proves that "some classes have more utility now than they did in WotLK", and not that "Almost every class has almost every utility" like you claimed. That's why I'm saying what you claimed was hyperbolic bullshit, and it is.
How much, then, is "almost every class". How many utilities are there in the set of "every utility", and what percentage of them are available to "almost every class"? Got some actual NUMBERS here, or is this just ass-pull fantasy you made up on the spot? Or are you seriously saying "we have more utility now than in WotLK, therefore almost everyone has almost everything" with a straight face?
That's a self-evident truth. It doesn't say anything about the QUALITY of what you're getting, just that you're getting less QUANTITY - which is not in and of itself a bad thing.
Oh, and, by the way: this WOULD NOT CHANGE if you took mythic away. You'd still get the same amount of complexity in heroic as you are now, because that's what constitutes the difficulty. So you're really not bothered by what you're getting at all, you're bothered that mythic people are GETTING MORE, and you're not good enough to do that, too; and so your solution is "okay let's just get rid of them, so I'm the one getting the most!".
That's incredibly petty, not gonna lie.
Reading what I said would be cool, for a start. You even quoted the part where I talked about this, but either your attention span doesn't survive line breaks, or you're being intentionally dishonest.
Okay, let's accept that (even though it's an incredibly reductive statement).
Now prove that this isn't actually how it works. Prove that "the game" is designed around "niche players" - not just that niche players also get content or that there isn't an exact match between percentages of engagement and percentages of dev resources, but that "the game" is designed "for niche players first".
That's a VERY bold claim. I hope you have more to back this up than "mythic players are only 1%! every class has everything! mythic players came to my house last night and ate my cereal and that's why I can't find my left sock! Ion personally cursed me to fail my algebra test!".
The problem here is that you think all content requires the same effort, and that there's any kind of direct proportionality between resource use and quality. There isn't. Some content takes far more resources to develop than other content; and for some content, a lot of work may increase quality tremendously, while for other content a lot of work may still not increase quality by all that much. That's... how development works. It's not a 1:1 kind of deal, never has been, never will be. MUCH LESS SO in a giant team effort like WoW where resources aren't simply fungible, and all the art designers in the world are not going to help your class balance team do better work.
You have no idea how things actually work, do you? You're just repeating some talking points you picked up on angry YouTube videos, without thinking for two seconds about how much of it actually makes sense OR IS EVEN TRUE TO BEGIN WITH.