This is just a random idea, I just wanted to throw it out there.

It's fun to create your own custom race for you, but how about creating custom opponents as well?
I know this can be accomplished by modding, but I wanted to suggest if it would be possible to do it normally when you start the game. Maybe each slot on the empire screen can be modified (rather than simply exclude / include)

I think you can randomize the personalities of the other empires if you want. But can you also change their pictures (and maybe their statistics)? Sometimes you like creating your own boogeymen or arch-rivals. For the totally random opponent, it helps to add to the suspense if you really really don't know anything about the alien races you encounter at the start (are they good /evil? militaristic?).

Thanks Stardock -- it's a great game. Hope this helps.