"Besides, while Resident Evil 4 looks incredible on the PS2, it doesn't look quite as good as on the GameCube, where it has richer colors, sharper-looking environments, and nicer lighting effects. Larger foes also look better on the GameCube (while smaller foes melt away faster when killed), and the earlier version's loading times are also shorter. Pauses during the interactive cutscenes are also longer by an instant on the PS2, making the interactivity feel a bit less seamless. So, since the underlying gameplay is exactly the same, the slightly but noticeably better-looking GameCube original ultimately still has the edge."
I don't want to turn it into another "PS3's graphics cannot match that of the 360" thread, but the hardware limitations are there. This is a fact. Whatever amount of tricks the developers use won't eliminate the GPU bottleneck.