This is good. I'd like to expand on it too.
Given the link up the game will have with the Stardock servers (to up and download mods, patches ect) I think it would be very easy to set up a "Game of the Month" like on the civfanatics forum. Give the pure single player a way to compare vs others. Games could either be from the start of a game or part way through, where Stardock has set up a tricky situation to manage. Eventually GotM's could be with quality mods. Allow users to upload their challenges to other players, eventually there would be a plethora of pre-started games for players to take hold of and get the high score for. Of course a save system based on Stardock servers would need to be in place to limit cheaters. Heck, on CivFanatics they are still hosting GotM's for Civ III.
I never got into the GalCiv thing, where there were clans and a galaxy to take over, was it successful? I could see a system where players are rewarded with goodies for achieving things. Goodies are not bonus in-game content, don't discriminate against the casual gamer, but nice little things like each player has a "hall" like in the original Civ, and the more you achieve the more you can add to the hall. Or whatever.
*edit* very bad syntax. very bad 