French fan site Half-Life 2 Fusion attended the Video Game Festival (Le Festival du Jeu Vidéo) in Montreuil, France a couple of days ago and met Erwan Le Breton of Ubisoft. The interview is very short, but includes some very interesting comments at the end. Here is a translation by yours truly:

Additional Features, SDK, Add-on, Sequel: Additional features will become available after the release of Dark Messiah. The software development kit will ship with the first patch. The release of an add-on is based on the success of the game. Ubisoft has been thinking about a sequel already.
Steam: Steam will be required for multiplayer only. Single-player can be launched without Steam.
Might and Magic X: The developers have expressed interest in creating a new Might and Magic game. However, developing a game of this genre is a costly and risky project.

About the last answer, we're not sure if Le Breton means Arkane or another game developer. In any case, it's good to know that Ubisoft is aware of the interest of fans and developers.