From: California, USA
The idea of quickly and easily taking BACK a break away independent is fine. It may be easy but maybe some bad circumstance might come up as a result of diverting forces to handle rebels.
Think of a real life city, even a large one including much territory around it, rebelling from it's nation. A swift reaction from the nation would be likely and easy; but there would be a cost and maybe negative repercussions.
Wish list:population centers beyond planetary(http://en.wikipedia.org/wiki/The_Culture):Ships,Ring Orbitals,Sphere Orbitals,Ringworlds,Sphereworlds;ability to create & destroy planets,population centers,stars;AI competently using all advances & features.