Everybody knows that each planet in the game has enemies in orbet, but they're all TEC ships, there should be a few of the other race's ships mixed in for variety. I mean if your a mercianary/rebel you will take anything you can get your hands on. (I'm assuming their mercanaries or rebels) And it can get kind of boring shooting the same guys at the start (note I said start, not middle or end where there's the other side to shoot instead ) of each game and I don't think it will go against the game lore. 10 years is plenty of time for a few of the Vasari's ships to get into rebel hands. (Advent not sure if that would fit as we don't know how much time they have been around, could be years or months, but would be cool if they did have a few floating around)

And if you don't like it forced on you, make it so it is optional. And be sure to include the neutrial colonies on custom maps too, the ones you can bombard. There are two kinds of nuetrial planets you know, the kind with just people in orbet, and the ones with people on the planet and in orbet. (Ie the ones you bombard)