That could make for some great tension, though. Dean goes to hell and gets tortured for years (from his perspective) while God gives Sam a get out of jail free card.
But the whole bit with the street light exploding over him makes me wonder if there isn't more to it then that. Maybe it's not Sam. Or maybe Sam's different somehow. Castiel is Michael now, maybe Sam is Castiel. Wouldn't that be wacked - i go to hell, god turns you into an angel.
(Not that I think that's what it is...)