I have a couple of suggestions, but as you guys know, I'm not really experienced with this game, so let me know what you think:
First, why have a separate Discussion forum and Faction forum? "Discussion" could be split into "in-game" and "OOC" and the in-game combined with the Faction forum, while OOC gets it's own forum to attempt to encourage roleplaying posts. That's also "Second," OOC needs it's own forum for the number-crunchers and such.
Third, between the ruling faction's own forum/thread, and the gameplay forum, I don't think another forum is necessary just for the ruling faction. The faction's forum/thread can deal with in-faction decisions, and the gameplay thread used to keep track of turns and stuff so that everyone can see what is going on.
Finally, I like the idea of a forum dedicated solely to history, maps, demographics, and other information about the nation. I guess another idea is to combine this information forum with a "Ruling Faction forum" to create a government forum. Here's what I'm thinking:
Main
-- Citizen's Forum (In-character discussions about the game. This also includes organization of factions. Factions could run themselves through a thread here or somewhere off-site)
-- Gameplay Forum (all threads related to playing the Civ4 game (think schedule and instruction threads))
-- Votes and Polls Forum
-- OOC
---- Game Analysis and Statistics Forum
---- Laws, Rules and Regulations Forum
-- National Factbook and History Forum (maybe Information Forum?)
I guess the problem I see with this is where the Laws, Rules, and Regulations forum is. If I was a new member coming to check this out, I might just disregard the OOC forum (and subsequently the LRR forum) completely as unnecessary, where in reality it would be useful to look through. Perhaps in the Citizen's forum and Information forum we could have a Sticky that links to the rules?