I seriously am in favor of some kind of expansion that involves actually directly attacking the AI's nerve center so to speak. That is, the exo-galactic everything that they've got. Depending on how it's done, it could feel like an entirely new game, or simply up the stakes tremendously by offering a game with tremendously powerful enemies. If the AI home-planets in our system are as strong as they are, how strong must their exo-galactic forces be? If you can bring AI Progress up so high that tens of thousands of ships attack you at once, one wave after another, how many ships are there actually wherever the AI is doing business at?