In most of my MP games the Graph is set to "Info on other nations is disabled" or "Score Graphs are disabled" in order to keep some semblance of mystery.

Half the time you get people who give up because they are low man on the totem pole, halfway through the game (Also people 'miss' turns, because they can't handle being Last sometimes) and the other half the time you have too much information than I feel is appropriate via a spy system. I don't like knowing every different field in which nation rankings are. It lessens some of the effect for me.