I've only ever finished a campaign when I used "Become the Crisis".
I think the game would benefit from scarcity being introduced. As it is right now, there's rarely a need to fight because there's nothing to fight over. If your deposits and planets could actually run out of resources, you would need to either negotiate trade agreements or fight over territory to keep things running and it would add a more natural and narratively coherent end to campaigns rather than the current system. Right now, some guys just show up in the 3rd act, completely unrelated to anything happening prior.