How about staggering the start dates of new games. I am currently playing in games 1 and 2 and have very mature airlines and the worlds themselves are saturated with other players. It would be enjoyable to have a situtation where one could be playing in an established world and a newer world for variety.
Not a bad idea at all, but maybe do a search before you post?
Briefly, the games currently running were the first public games so there were a lot of people wanting to play and several games started at almost the same time. I can not see why Sami would not do what you suggest in the future and I believe he even hinted something to that effect when the issue was last discussed.