It is similar, but not totally. I was thinking even more decentralized, where cities could choose to attack each other, and have their own militaries (which, in a war they don't support, they could withdraw their militaries). As I see it, in the realpolitik game, the city governor has little/no power beyond managing it's tiles and voting. In my vision, the advisors (military, scientific) suggest possibilities that the city leaders may or may not act upon.
Some more ideas to throw out there, however, I can do.
Game:
Players will take control of one city in an empire created by the game master (the person who inputs the commands, maybe myself) who is not in command of a city, and thus is neutral and will not put one city above others. Players, at the end of the game (we will be playing for a time victory) will be awarded points depending upon the amount they have achieved divided by the amount of time the city has been existing (to give late-game cities a chance). Points can be awarded by things like commerce, science, culture, wonders, military (units and amount of victories with army, to encourage fighting), vassals (ie. cities can have dominance over other cities) as well as a "diplomatic vote" where every city will have a vote as to whoever is the most liked of the group (you can't vote for yourself

).
Government:
Similar to the demogame, realpolitik, etc., there will be a gathering of city leaders, who will vote on issues such as: Science priorities as advised by the science advisor or otherwise, targets to attack as advised by the military advisor (or otherwise, again). Perhaps diplomatic, civics and the treasury slider could be included as well.
As for the aspects of city-specialization:
For commerce-related cities, products from GP farms or production cities could be bought, as well some sort of bonus for contributing heavily to scientific research could be had.
For production-related cities, products from production (buildings, units, etc.) can be sold for other commodities (culture, commerce, etc.)
For GP farms, GP's can be sold to others for commodities.
This is just after a short 10 min brainstorming session, there can and will be much more, but I would like some input so far.
Also, there can and will be civil wars. (using units to pillage other cities improvements, "hiring" barbarians to attack other cities, etc.)
So it should be a heck of a lot of fun.
