I really had fun with XCOM 2, and personally, I didn't experience anything but fairly cosmetic performance problems. If you look on the internet though, you'll see I appear to be quite unique. There are many who have had problems with the game, and the claims are pretty widespread.
It seems that these issues caught Firaxis by surprise. Speaking to RPS, the game's lead designer Jake Solomon explained this caught him unawares, and that the team is currently working incredibly hard to right it.
Maybe this is damning on me, but I'm sitting here talking to you now on the laptop I use to play it on and I didn't see these issues. We didn't catch this stuff in compatibility testing. We're fully, fully accountable for the product in people's hands, so we certainly take responsibility for it.
To people who are suffering them, if they're frustrated, I'm as frustrated and more. We will continue to update the game, and we do have some workarounds – heck, you guys even posted some workarounds – but we definitely have fixes coming soon.
While he couldn't commit to dates, he said the dev is hoping to get it out asap.
It's a shame to see the game being hurt like this, because for those who don't experience issues or when it is running smoothly, it's truly excellent and one of the genre's best. I hope this gets sorted soon.