A couple months ago I asked if Steam would be required and was told they had yet to determine that, and were considering several possibilities. Presumably that means the Steam client isn't required to use Steamworks, or at least only required when using that function (online multiplayer or user made DLC).
Unfortunately that sounds to me like Divinity: Original Sin will be a Steam game. Because the fact that it would be possible that the steam client is only required for online multiplayer doesn't mean that it is going to be so. Do you know any game with uses the Steam Client for online multiplayer but run in single player without Steam? I'm pretty sure that, if the game uses steamworks, it will be a steam only game. And that would also mean that there won't be a (steam/internet independent) lan mode. Wouldn't it be better to use direct connections to play together? Yes I know many people would have problems with port forwarding and so on. And in times of steam it's all much easier (and more dependent). Is there really no solution except steam. How did it work in times of Warcraft 3?