What I don't get is why they keep dumping their gimmick every gen. Megas weren't perfect, they were centralizing, generally overdesigned, sometimes downright overpowered, and badly distributed, BUT if they had stuck with them, and tweaked the existing ones (rayy lmao, kanga, etc) and continued distributing them they could've added a lot. As they became distributed the centralization would become lessened and they could've used them to boost shitmons since they had tested the concept on popular mons. Hell, some stuff that was shit before, Mawile, Kanga, etc became legit massive threats. I think that gimmick could've even coexisted well with regional forms if they wanted to go that route. At the very least it was fun to see how Pokemon would change with new types and abilities.
Z-moves were always a bad idea because they were just a gimmicky kill button, and dyna/G-max retains abilities and just boosts hp(?) so it's basically just a three turn long kill button. Hell the three turn limit could've been applied to megas and it would've been far more interesting than what we have now, besides them not having to scrap everything and make new shit each year. It's baffling.