After reflection I think I would Have been happy if they had wrapped up the jack/chuck arc and had the remaining episodes inthe Mrs Butters bunker. They would use the m ster hunter and kill monsters, return to the bunker and have a hot meal. Dean would find a girl, Sam would continue to date Eileen. Eventually they would find out they were in Heaven and use the telescope to see and contact Bobby and others and find out what was happening on earth. At the end they would learn how to go back to earth to help with some crisis. End show.
Jack really is wearing on me.