I was able to get D2 running (again) on Win 7 x64 by using a trick I read in another forum (the Robin Hood forum on Steam actually lol). Basically, you use DXWnd to start the app (or Steam with DXWnd running), and the only real change I used to get things working was to select "Handle Exceptions" in the "Compat" tab. Here are the (modified) instructions:
1) Download the latest version of DxWnd from... http://sourceforge.net/projects/dxwnd/files/Latest%20build/
1) Unrar and inside the extracted folder run "dxwnd.exe" as administrator (if you need to). Go to "Edit->Add", in parameter "Name" set the name as Divinity II.
2) In parameter "Path" choose the .exe file of the game (in my case it looks like M:\SteamLibrary\SteamApps\common\divinity2_dev_cut\bin\Divinity2-debug.exe).
3) In the "Main" tab, under "Generic" untick "Run in Window". Also in "Main" tab, under "Position" set "Window initial position & size" to X=0 and Y=0. Set "W" and "H" to your native resolution (in my case that's W=1920 and H=1080).
4) Next in "Input" tab tick "Hide Cursor". If the cursor flickers on the main screen of the game don't worry, it works fine in-game.
5) In the "Compat" tab select "Handle Exceptions".
6) Lastly click "OK" in DXWnnd, if all is good it will show a green circle before the name of the game in DxWnd.
Now you can start D2 from either the DXWnd app or start the app and then launch from Steam
There is also a "Fake Version" mode (for OS) in the "Compat" section so this could be a solution for other operating systems too.
What I think is happening is a soft error on startup that is not handled properly by D2 (shame on you!), so it just crashes. The DXWnd app actually catches the error and just ignores whatever happened..and continues to start normally.