Here's a quote from another thread:

I originally planned to respond to it in that thread, but I soon realized that it is such a huge topic that it warrants its own discussion thread.

Diplomacy is one area that has been severely neglected in all of gaming. The only game I've ever played that had good diplomacy was an MMO called Shadowbane (and the diplomacy occurred between real players and involved the real consequence of losing your city).

Metrics are totally the wrong way of doing diplomacy. You can't quantify a real person's opinions or a culture's customs with some silly numbers. You can't quantify hidden agendas or secret agreements.

A few key rules should be followed when designing the diplomacy system of a game. The AI-controlled players should:

• Never give away any information unless it suits their agenda to do so
• Never make their decisions in a random or otherwise non-deterministic way
• Never treat the human player(s) differently from how they'd treat their AI rivals
• Always seek to maximize their position in the course of negotiations

All of these rules have been broken by games in the past, to their detriment.

• The AIs would leak information like crazy, including all of the technologies they possess, their opinions about all of their rivals (including you), their goals and desires and even the fact that they are preparing to attack you.
• The AIs often behaved in random, non-deterministic ways, accepting/rejecting a trade offer based on a random variable (frustrating and stupid, if you ask me).
• The AIs ganged up on the human player, having been programmed with an "us-vs-him" mentality.
• The AIs allowed themselves to be manipulated in trade negotiations, to be bribed and controlled into ruining their own plans and wasting their efforts.

Obviously, the design of a diplomacy system is much more complicated than following a few rules. There must also be a strong strategic foundation for the AI which allows it to formulate realistic goals and take the necessary steps to achieve them. AIs should be able to "see through" a player's gestures towards them and find weaknesses to exploit.

If a player is weaker militarily than the AI but stronger economically, it should not allow the player to bribe it into abandoning its plans for invasion. Rather, it should attempt to suck as much gold, mana, spells and other bribes out of the player that it can to further bolster its position.

This type of system is very hard to design, I admit, but I believe it is worth trying. I hope that the scripts and routines used for the AI are open to the modding community so that modders can fix any glaring mistakes or loopholes in the diplomatic AI.

What are your suggestions to improve the diplomacy of this game and elevate it over the mistakes of the past?