I've been having this problem since the Beta but it's got considerably worse over the last week or so to the point where the game is completely unplayable. It had been just textures and the odd world object not loading but now has escalated to enemies and the basic game geometry of walls and floor, leading to frequently falling through the floor into space, or getting into combat with enemies I can't see, shoot, damage or hit with skills but who can still kill me.
Here are some examples of what an average play session looks for me now (plus a screen of my benchmark results): https://imgur.com/a/MyyY5WD
I've tried repairing the game from the UPlay client twice, it's found no problems. I've tried setting my graphics to both lowest and medium with no change.
DXDiag: https://pastebin.com/A5Yav2K2
It didn't initially but after a subsequent Windows reboot to install updates it's been perfectly fine, better than ever since launch. There's been the occasional time I've entered a new area and it's taken half a second for objects and textures to pop in but that's such a minor issue in comparison to how it's been.