It's my personal 2016 GOTY, but the issues you brought up are indeed very serious. I was able to push through, but the problems with the camera, AI, performance and movement, even taken individually, are absolutely deal breakers. I don't blame anyone for giving up, but it still makes me sad since I love the game so much.
Prepare for the defenders to tell you that all that is completely intentional
I don't mean this as a defence, but I do think the weird camera and movement behaviour was (mostly) intentional. They seem to constantly try to direct your attention to specific points, usually a nice view, a puzzle solution or Trico. I don't think it worked as intended. Also, the free camera movement is so cumbersome with the half second input lag and constantly getting caught in odd places. Mixed with lower framerate areas, this is nauseating.
The movement looks very natural, but it comes at the cost of precision and results in awkward and unintended behaviour, as well as annoying deaths.
Again, I think they were going for a very artistic approach to the gameplay, something I actually find really interesting, but that just didn't work in practice. I won't defend it, I think more thought should have been put in to make it comfortable to play as a game, rather than an art piece. I'm not sure "artsy" gameplay can really be done outside of something of very restricted scope, but I hope someone proves me wrong one day.