in the first place nomura states that king mickey, went to look for the keyblade he has now. the keyblade did not necessarily chose him. as for the keyblades beig dark, light twilight i just don't see it. i mean sora wielded the oviblion, and he was light back then, what makes the keyblades any diff. now. actually if u think about it they don't have any meaning there're just keychains, there's only one keyblade, anyways.