Wanted to share my experience from the last 3 hours of game crashing, re-installing and finally bug hunting. I found the reason for the crashs...
When changing on a fresh installed game with no mods the graphic settings to "Low" preset or specifically "shadow details" to "disabled" (the option above 1024x1024) the game will crash in loading screen.
you can fix it in pdx_settings.txt in C:\Users\%username%\Documents\Paradox Interactive\Imperator
change "shadowmap_resolution" from value="disabled" to value="1024x1024" then your game will start again.
@Paradox / @egladil
regarding forum post "1.3 Crash on Startup"
a small thank you would have been nice