Thief 3 appeared to be slightly disappointing, especially AI seemed to be lacking something. And after I saw some screens of DarkPlaces in Quake1, I thought, it would be the perfect backbone for an OpenSource-Thief-styled game.
Here's a screenie comparison between the Thief games and LordHavoc's Quake pics.
Thief 2 - The Metal Age
Thief 3 - Deadly Shadows Screenie1 Screenie2 Screenie3
DarkPlaces Quake Screenie1 Screenie2 Screenie3
Imho these look quite comparable. At least the level of darkness is very similar.
I can say, that I've played every existing Thief game, including the ThieveryUT-Mod, which had a very enjoyable and innovative multiplayer mode.
An OpenSource-version of this heavily underrated type of game could become pretty popular (since there are no attemps to continue the franchise afaik) and would be simply awesome.

Here's my first concept.
