the engine is starting to break new ground when dealing with dynamically scripted missions. you could set up a series of missions as backgrounds only, a few for each system on the node map. when you go to a jump node the mission that node links to would be the other side. also you could intra system jump to different parts of the system youre in, loading the proper level each time. local traffic could be automatically script inserted into each mission. such a system would limit the complexity of missions, since you cant sexp them (because everything is placed in the level at runtime). you can however have regular sexped missions that you can get to at different points in the campaign. things like economy, reputation, ect could be handled entirely in script. youre actual progress could be stored in script generated files.