Maestro, why do you want to reduce choice? That is counterproductive to encouraging more players (even just paying ones) to play.
You seem to have a 'more-is-less' attitude to the game. You're arguing for fewer choices, fewer options. What attracts people to this game is the range of different ways to play. If you can spend 24/7 at your computer, you can play 10-country empires on all 5 worlds, and some of them are very fast. But if you have limited time, at the moment you can still play on one of the slower worlds and keep up with the way your empire develops.
If you limit this game to the people who have time to play on all 5 worlds, there won't be that many left. Given that the game is already limited in who it attracts (those who appreciate a long-term, numbers-based strategy game, as opposed to flashy graphics and immediate gratification), there won't be many players left if you limit choice that far.
If you want to put forward a persuasive argument, think about the bigger picture, not just what would suit you.
Hugs and respect
Jo