Oh yeah, aside from the fact that the game was initially intended to be an online project, with 48 colossi, which were cut down to 24, then down to 16, and that Ueda admittedly abused bloom and frame-based motion blur to mask the 15-20 frame rate. All deliberate artistic choices.
Hajime Sugiyama of Team ICO specifically said that they wanted to do Shadow of the Colossus on PS2 even with the PS3 around the corner. SOTC isn't the result of hardware limitations because the PS2 had everything they needed to realize their vision