I as a Mac fan always thought about game center on Mac. And today apple said it will.
So I am thinking could this mean that if you bought civ5 on the app store shall it interact with game center. Maybe this is going to be also the next big thing for civ5 because game center uses iCloud and that means your iPhone ipod touch and iPad are involved with your civ game.
Also many people are saying that a iPad 3 will be comming out soon and might the iPad 3 have a processor powerful enough to make the full version of civ 5 on iPad.
Who knows what is your thought