Oh I see. I'm the opposite in this aspect :) If we have SURELY 5 seasons, I'd like for this one to end in a not clear way, or even badly, and to have the final resolution in season 5. I would have really liked a Sam vs Dean showdown some point in the story, but I don't think Kripke will follow this route. I mean, I'm pretty sure he would if he could, but I think they will not anyway.
But hey, whatever happens, I so would want Dean to save Sam, and see them finally return to their old co-rependent relationship of mutual adoring brotherly love :)