Wow, very good idea! I have one, too:
At the end, when Leo came back the angel that brought him back said that there is one person who needs to be there, too. Nobody said something, Phoebe looked confused but Piper had tears in her eyes and whispered: Prue!
Then the angel makes Prue come down with shiny lights around her and says that she has a second chance, her last but without Andy and the other ones she learned to love over the past 5 years in the clouds (or wherever
). Everyone hugs her, all hug each other it´s a wonderful familiar moment. The angel disappears and around the Halliwells are these shiny lights that become more shiny, the triquetra appears, flashes and then it´s getting dark. The end!
Sorry cuz it´s really different with the real end but I want Prue coming back! I miss her! So she should become this second chance, even it is maybe impossible... kiss