Game Pro had a chat with Civilization 5 lead designer Jon Shafer, you can read it over here.
This focus on history is deeply relevant for any designer of the Civilization franchise. Even if you don't have Shafer's degree in history, Civilization already has an enormous advantage by being set in real places, using real technologies, fighting with real weapons. "You don't have to read a manual and figure out the rules of the world," Meier explains. "You get that chariots are cool and that gunpowder will be handy to have at some point-and that Genghis Kahn is not to be trusted." Even the most novice players (such as those Meier is hoping to attract to his upcoming Facebook version of the game, Civilization Network) immediately understand basic concepts like irrigation and sanitation and can skim along the surface of the game before diving deep into the mechanics. It's this sense of familiarity that makes Meier's sandbox that much more fun to play in.