I guess I've been thinking of it as a master race attacking either to take the system for the hospitable planets, or perhaps to enslave the less advanced species. Not sure on that count. The game would progress as a campaign jumping from system to system completing missions of some sort.
Thanks for the input!
Sure! Just saw you had a journal started, too, I look forward to keeping track of your progress.
Edit: I like StormyNature's direction. I remember in Master of Orion II (classic turn based galactic-scale strategy game) when two other species would fight, I would feed the weaker side advanced technology so the war would wear down the stronger, leaving them open to my fleet.
But seriously, I could write a space opera for every Master of Orion save I have.