IMO Mythic+ is the biggest problem with the feeling of grindiness yet total stagnation that retail has.

You farm the same dungeon over and over and over progressing from regular Mythic to +10 or 15 or 20 or 30 or whatever the max is to get the highest ilvl version of your BiS item. Raid gear is irrelevant because all dungeon gear is perfectly itemized and simply scales to raid gear ilvls without ever touching the raid. You use your M+ gear to faceroll the raid for 6 months until the next raid comes out and all the M+ gear scales up to the new raid's ilvl, so of course instead of doing the new raid for your upgrades you have to go back to the same fucking dungeon you've done 1000 times and hope the the same piece drops again at a higher ilvl.

It's horrible design, top it off with an oppressive helping of RNG and a mandatory AP grind and you've got a recipe for the worst gameplay cycle ever in MMOs. It's a wonder people still fool themselves into playing BfA, there are actually no redeeming qualities to this expansion whatsoever. Shadowlands will be the first expansion I won't buy at release solely due to the fact that BfA was/is such garbage.