>>47573445personally I dislike it due to the drastic drop in content (especially compared to its predecessor) and the very bland soundtrack but I can't speak for others
megas would've been better if they weren't mostly postgame and were given to more pokemon that deserve it instead of half the fucking pseudos around at the time (who tf was asking for mega ttar, seriously)
the visuals also haven't aged well but i'm gonna be bold and say they look better than swsh, they really take advantage of the new medium with how dynamic the camera ends up being and places like Anistar or Laverre look fucking great on the 3ds
anyways enough of my personal opinions
as for everyone else, from what I can generally gather it's a combination of
-being the beginning of the end
-being very obviously rushed
-having an intrusive and nonsensical plot that doesn't have the decency to keep its shittiness out of your face
-bland models and animations (though I think this complaint is more of a thing now because the next 2 generations reused them with 0 change, and less so an actual issue with the game)
-extreme forgettability
-increased linearity and excessive handholding
-atrocious rivals
-0 lore surrounding any legendary or mythical other than the box legends (though this complaint is far rarer and obviously more minor)
-lack of third version to iron all the shit above out and improve the region
-essentially no postgame (a 1 hour sidequest and battle tower clone doesn't count to most people)
feel free to correct me if I missed something or misinterpreted another