Ok and here we go with triple post
After messing around with the CCC and some presets nothing worked out so I tried some other tricks regarding the graphics and setting the response for the graphic drivers on 10 (decimal) within a new registry entry stops the game from crashing right after loading but leads to a crash a while into the game.
So the issue definitely is an issue with the graphics drivers (the most recent of AMD in this case).
Guess you guys will have to put some work in there again and you should not wait too long with it as Steam community already is pretty upset regarding this (and other) issue/s.
Maybe an announcement on steam regarding issues are known and will be worked on ASAP would benefit your reputation there.