Hmmmm.. a lot of interesting ideas here.
Spies- ultra cool! let's face it, info leaks are a way of life on most, if not all, countries. It will depend on each players (by player I mean the entire civilization) values to spy or not to spy. But the game makes it available, let's not stip it off the table too hastly. If both players agree to the posibility of spying and counter-espionage, it makes the game a lot more interesting.
Aliances- interesting but boring. An aliance very early in the game could make us a bit laizy, since we wouldn't have to worry too much about the other player. Aliances should be made when there is something to gain (or loose) and not just for comfort. Anyway, to deny us the pleasure of actually holding a war campaign against another human being and not just the oh, so predictable AI would be a shame.
National security - An honor code would be ideal. Ideals are very hard to reach. Someone mentioned a password, that would be the best alternative. We would need to have, however, real life embassies on the other's player forum. That's something to think about.
Anyway, those are my two phoenaticans worth. I vote yeah! let's do it! after it's aproved let's get into the intriquesies (sp?) of it.
Ehecatl Atzin