This might be a strange thought, but for some reason I don't see this playing out like a normal Metal Gear game. If they try to make it about the badass Raiden from MGS 4, I see it playing out as more of a Dynasty Warriors-esque game in the Metal Gear universe than the stealth based action that we all know and love.
Overall, I'm skeptical of how this will turn out, but I'm not going to let that dash my hopes that this game will live up to everyone's expectations (and that Raiden won't be as much of a pussy as he was in MGS 2).