Now that religions are in the game, it would be great if the Televangelist from Call to Power made an appearance in the modern era (reflecting, perhaps, the influence that mass media has had on the dissemination of religion, e.g. the Christian Broadcasting networks, 'trendy' Buddhism in Hollywood, Islamic networks in the Middle East..etc..)
"Open your wallets to Salvation!!" *waves hands in the air*
It would also be interesting if there was someway of fitting propaganda into the game, perhaps by constructing a propaganda centre in the modern era and then tasking a city to 'build' a propaganda campaign which is then directed at a particular city, causing that city's cultural influence to decrease/unhappiness..