Performance-wise they're a mess, but I also think these games introduced some of the best ideas in Pokemon in many generations, and they've been my favourites by far since Generation VI. There are lots of super fun easter eggs, character designs are great, terastalising is the best and most complex gimmick since mega evolutions, and I actually thought the story was interesting this time around. I think they got too much hate for what they are, which in my opinion is the best Pokemon games since Gen V.
Should Game Freak be spending more money on larger development teams or more talented programmers, to ensure games run smoothly and graphics and animations are better? Absolutely. But are the games awful? I really don't think so. I thought they were super fun and I enjoyed them a lot.
For the first time in years Pokemon genuinely felt like going on an adventure with awesome monsters, discovering stuff about this weird world and it’s wacky characters, instead of a linear demo with very little spirit. I’ve never cared much about a game’s performance or graphics, so I didn’t mind that much, but I feel like this game has more soul than X/Y, Su/Mo and Sw/Sh and that is a step in the right direction for me.
For single player gameplay, I found terrastelizing very boring. It just makes one type stronger. Of the few NPCs that use it, they almost all waste it in extremely dull ways.
Nothing has yet to come close to megas, which at least we're really fun to find the various forms of and breathed a breath of fresh air into a few species.