1. Although I have all maxed out (with no AA effects), there are no shadows for the npc and enemies.
Same here. Everyone else has this "issue" (I don't think it is, guess, these shadows wasn't implemented at all, so, why bother).
3. If I try to uncheck the Shadows timeslicing refresh I have a dramatic drop in perfomances.
Don't do that then?
4. Don't know if this is related to point 3, but most of the shadows of trees keep forming with layers upon layers, depending on the distance between my char and the object. They change in realtime according to my movements. Here are two pics:
It's LOD. Usual thingie (no, I didn't saw screens, too big size)
6. Is it possible to get rid of the dialog box about the Physx drivers before the Larian logo ? I have a different drivers set on my pc, no problem with the game since they are all up to date, but I must always confirm the dialog box, which is kinda annoying.
Not yet, but you can request that feature while the patch is still in development.