One thing that struck me both in this and the previous campaign - would an alien race's reaction to being attacked by human scum be nuanced enough to only go to war with a single empire, or would they attack all the empires associated with that race? You might want to put in the possibility of negative diplomatic events spilling over into affecting attitudes towards other empires of the same race too....
John
Or as a future possibility further distinguishing between race and empire. Who says that humans are the only race among the stars that can have several different factions/empires within?
Awesome possibilities to have an alien race divided into several empires and while an all out race-race war would see humans lose badly you could outmaneuver them by triggering an internal war between their factions! And then strike while they are weakened (or alien NPRs using the same strategy against you... )
Would be really cool if this was a race setting so some races are united and fight united wars against all factions of an alien race in response to the aggression of any of it's empires. (only one empire allowed for the race with this setting).