Point of clarification in my Witcher 2 review after talking to popo last night:
Having looked at side-by-side comparisons, I can definitely see the contrast with the two graphics engines used, but having played the first game on PC with max settings on a 24" screen and the second on an Xbox 360 on a 65" screen, the texture quality - what I mainly look at when I talk about graphics - looked pretty similar to me, especially considering the couple months between my playthrough of each game.