One of the things I miss mot of all when I complete one of the Campaigns, is I can't do them again. I like playing with my Hulls sometimes, and seeing how they compare, to others, yeah the Campaigns aren't the only thing that is out there like that, but I find them fun. I think it be cool to be able to go back and play Mastery level even after you have completed it, just for fun. If reward is needed/wanted, could always put Tokens or crew as rewards (Though, I would think that would mean a time limit between the times you can complete them, like a week or a month). Personally, even without tokens or crew, I'd still play them from time to time. Just an idea I had and liked the idea of maybe possible crew or tokens as reward (like I said, personally wouldn't mind no reward, killing the Campaigns again for the hell of it doesn't matter if their is a reward).
Fighting among ourselves only helps the Draconian Empire stand back up, stronger than ever. They might be weakened now, but it is naive to underestimate them.