Originally Posted by ynnek
Honestly, besides the shadow's, Thief feels and looks like an older engine.
Er, that's basically true of every engine (but you forgot about the bump-mapping). Play Doom 3 and disable shadows and bump-mapping, it looks almost exactly like Quake 3, but that doesn't mean the engine isn't advanced. And really, I don't see how you could play CS:S and then say that Thief 3 feels like an old engine...CS:S practically looks like CS with pixel shader effects (and of course higher-poly models, but that's hardly engine-specific).