I have played every gen and this had unequivocally the worst plot of them by far. The story of the gym challenge was entertaining enough, nothing special but not bad either. It almost seems like they were afraid of fully removing that last chunk of the game involving legends/evil team. The thing is, there were so many ways to have salvaged the plot (it still would have been mediocre, but at least not awful). Humanity today doesn't give a shit about problems in a decade from now let alone 1000 years, so the plot was hard to relate to. Instead, why didn't they just make it so Galar was immediately about to run out of energy? Perhaps the Championship Tournament would have pulled too much Dynamax energy and permanently black out Galar. Add in a segment about actually going to where Eternatus was found, fighting a few more of those Macro Space guys, and it would have been serviceable. Really the only interesting part of the main quest to me involves Team Yell and their motivations. Beef up that plotline a bit and it could have fit more into the immediate energy crisis plot and been pretty great.
Then to make matters worse, the Post game brings in two random, irritating, and awful characters who never once showed up in the main game. Admittedly, their plot and motivations were somewhat better than the main game, but it just feels so tacked on, especially when you consider this is how you obtain the mascot legends. Its especially dumb that they literally just reuse all of the same areas rather than make new ones for you to explore.
I really enjoyed other parts of the game: the new designs are all fantastic, Galar is memorable, the gym challenge was epic. But man they dropped the ball so hard in the story department. For people saying Gen 6 had the worst plot, at least the villain had actual motivations and there was some buildup.
