Just an idea that came to mind, but it would be neat to have a small unique perk per race for the campaign. For example:
Federation: There’s a random chance a planet you own will ask you to escort a freighter to another planet. Upon completion, you are awarded with a sum of credits dependent on the distance from a-b and how many hostile planets were in between them when the mission was issued.
Rebels: Ship-yards you own have a small chance of producing a random ship design you have for every turn. So you start the turn and one shipyard might go pop another ship has joined your cause!
Swarm: As the battle progresses and the enemies % falls below 50% there is an increasing chance (higher chance per ship as the % drops) that enemy ships will turn around and run away from the battle.
that is all i can think of right now, but it would add some spice to the campaign in my opinion.