It would be interesting to know where Crusade was going over five years. I don't think JMS ever revealed details of the overall plan for the series arc - just bits and pieces about how the first season would conclude and the second would start. I think we'd have seen versions of some events in the Technomage, Centauri, and Telepath book trilogies brought to the screen. Like B5, the outline plan would probably remain intact but the details would differ. It would have finished its run 17 years ago had it lasted five seasons.