Maxwood
Oh rock of ages, do not crumble, love is breathing still. Oh lady moon shine down, a little people magic if you will.
Third time I booted up the game GFWL was magicly there.I just verified the integrity of the game's cache and GFWL is still there. As soon as I launched the game immediately started installing the Minerva's Den patch, which is par for the course as the Steam version is out of date and has been for over a year now.
Go to your game's main directory and see if there's not a file titled "xlive.dll". If it's there then there's still GFWL integrated into the game.

Ah, well.
Maybe I forgot to save, or it has to do with GFWL missing, but I had no savegames. And it started crashing while checking for DLC. After allowing steam to backup saves to the cloud it works, though. :/