As i said before,Deadly Shadows=Deadly to the frame rate. I hope this doesn't make the game as slow as molasses as DX:IW. While u can get away turning off shadows in DX:IW,in Thief that makes it as bad as cutting off the fingers of a pianist.
The previous Thief games did not have to benefit of DirectX 9 technology,but that did not make it any less immersive,or fun. In fact i am still playing games like Thief 2 and Fallout occasionally today show that gameplay still rule over useless eye candy filler designed to substitute over gameplay. How many times can u look at pixel shaded water and casted shadows and say "wow" if the core gameplay stinks or stales rapidly?