I think this gets at the heart of the problem with using Rich. His best stuff came after he had been well established as Nova. Sam has the better "drop in" origin story, especially since the Nova corps has already been destroyed.
The down side is that his story is also basically Star Kid, and that movie was dumb. Maybe if they kind of thrown Sam, Star Kid, and The Last Starfighter in a blender you come out with a pretty cool movie.