Since mythic plus was introduced with each expansion its getting worse and worse.
Now with legion there are a few things why/what made mythic plus such a great new feature.
1- the obvious is that it was just a new feature that gave something a ton of replay ability.
2 - dungeons weren’t designed with mythic plus at the forefront. Blizzard had no idea mythic plus would have been as popular as it was. So each dungeon was made unique. Some dungeons had 3 bosses and some had 5 bosses. It made each dungeon feel different.
3 - Tyrannical and Fortified didn’t start until a +10. I think this is a huge reason why mythic plus hasn’t been fun that past two expansions. Keys didn’t have any affix until a 4. Which I think this is how keys should be today. A 2 should just be slightly harder then a base dungeon. Tyrannical and fortified makes a 2 significantly harder then the base
4 - the aoe cap. Now this a new problem with shadowlands. In legion each spec, well most specs, could compete with one another in mass packs.
Now with Bfa and shadowlands mythic plus isn’t fun or as fun as it was in legion
1 - the new factor is gone and affixes are the same recycled thing, but now we get seasonal affixes. And those can be a huge miss if they aren’t fun. Because now you are forced for a whole season to play with the seasonal affix for every key at 10 and higher. It was nice that legion didn’t have this. Meant each week felt different.
2 - now plus is designed with it at the forefront. Each dungeon now feels the same. Pretty much same timers, same amount of trash, and same 4 bosses (mists has slightly changed that which is a good thing.) it’s okay that one dungeon has only 3 bosses and a fast timer. It’s okay that we have a halls of valor with 5 bosses and a longer timer. It makes each dungeon feel more unique. Now each dungeon just feels stale.
3 - we now have tyrannical and fortified right away at 2 and above. With how dungeons scale keys really don’t need those affixes at all. But the truth of the matter is having theses right away hurts new/casual players from getting into mythic plus.
In legion a 2 and 3 were just slightly harder then the base. This meant new and casual players could see how mythic plus worked with the timers and also see that these dungeons were slightly harder.
Those players now see right away at a 2 how punishing some bosses and trash can be. This is bad for the health of the game.
4 - and we all know just how bad the aoe cap is.
Now probably nothing will change this expansion, but hopefully blizzard goes back to a legion style of mythic plus. It was truly the best time to do keys.