I agree, holdphone, that Raiden became really dumb and pointless in MGS4, but his role in MGS2 was no less meaningless. I know what Kojima was going for... he was going for an innocent soldier, the kind of soldier that actually had emotions and reactions to his situation, to counter Snake's cold cynicism and monotone acceptance of his role. It was a cool concept but Hideo's writing skills (or the writing skills of his team) were not up to capturing that in dialogue. It came off as stilted, overblown, and unrealistic. The running theme of Raiden not remembering what day it was had small enough value that it should have been scrapped and replaced with something more identifiable, and any humanity that WAS contained in the character was washed away by the colonel turning into an alien and saying shit like "I like flowers."
In other words, MGS2 lost its focus.
Note to gamers: when someone shoots you in the face, they aren't "gay." They are "psychopathic."