I think what most people believe is that the show should have ended with Sam sacrificing himself by jumping into the pit and saving the world, that's it, he doesn't appear again watching Dean and the girl. The Devil wouldnt have won but it wouldn't have been a fairy tale ending either.
I personally think that's what was written in the original script as the ending until they were told to drag it on for another season or however many it does run for.
I agree with Blackbox completely, the show probably should have finished but I'm glad they are continuing the show as long as the next story arc is as good as the last 5 seasons worth.
It will be interesting to see how they continue the story as every interview I have read says that it was always going to be a 5 year story arc..does that mean all the angels and demons and Lucifer are left behind and we get a new bad guy? or will the Apocalypse story continue somehow?
Has anyone heard anything?