So I am using Win10, Steam, Sacred 2 Gold, CM 1.6, Elite Textures and I got it to work with the "run as admin" - option in combination with the compatibility mode set to Win XP SP 3 and the starting params like mentioned above and I could play a little. I found this guide at steam forum very useful for my issues I had before: http://steamcommunity.com/sharedfiles/filedetails/?id=166938930
For some reasons which I don't know, it might be an Windows Update, this settings did not work any more. The only way to get the game then running was to start already Steam with administrator rights and suddenly the game worked like before. Hope that helps!