I agree. It would be great if you could change the name of both the empire AND its 'ruler' every so often. At these times, your civ-traits might also change according to how you have been playing the game over the past X turns. So, for instance, if your expansionist/industrial civ has been focusing very heavily on war and religion, then when you next change your government, your civ traits might change to religious/militaristic.
I think that these ideas will give Civ4 a much more 'organic' and 'immersive' quality, and will significantly increase the replay value of the game!
Yours,
Aussie_Lurker.