Do a live stream to test people's reaction to things like Covenants? Seems a bit redundant, as they knew damn well what the reaction is.
But anyway, back to the other thing. Imagine what would happen if they capped m+ at 15. Here, I'll help you out, because for some reason you aren't trying hard enough
Take the Covenant instance buffs, for example. As is, it's pretty obvious those will be mandatory for groups pushing the highest levels, right? "Because every bit of DPS matters" - which, in this case, is actually true. And here you have it: the mere existence of things like infinite difficuly scaling creates this friction between player power vs RPG choices. Because out of sudden, if you cap m+ at 15, it's not "mandatory" anymore; it's maybe "quality of life". Sure, PUGs might still look for people with specific buffs to make it easier for themselves, but for organized groups, those buffs won't matter as much anymore. And then your m+ player doesn't have to sacrifice RPG for the ability to do highest end content.