I haven't actually fleshed out much of it because it is typically one of the last things to get implemented into a strategy game (unless there is a super huge diplomacy focus). I also held off thinking about it because this is primarily a multiplayer game, which means that a lot of the diplomacy doesn't always need to be hard coded.
The absolute basics that will be in the game are:
-Alliances
-Nonaggression-Pacts
-War
-Trading
-Voting system for Emperor and any other positions.
How much further should the diplomacy go? Here's the restrictions we have to work with:
-Players cannot be guaranteed to be online at the exact same moment. This is essentially glorified PBEM.
-Players use their own system to evaluate trustworthiness.
-There will be some AI factions, but they do not function in the same sense as the player. Their decisions will be limited.
The primary questions I have are:
Should treaties be immediately breakable at all?
If they don't have any consequences other than loss of trust from other players the trend becomes never actually making any more than verbal agreements. By "breakable" I mean they would either have time limits. Another idea would be to have them only breakable by sending a canceling message on one turn followed by the automatic dissolving of the treaty X turns later. Treachery is fun, but when there are so little consequences for it it really doesn't even become a decision.Similarly, should there be an artificial game mechanic that penalizes players for breaking treaties?
These options could include things like:
-Loss of standing with few AI factions.
-Actual monetary fines from the Emperor.
-Faction wide morale or production hit or something for appearing dishonorable.How should communication work?
I figure I can't stop players from talking outside the game so I might as well just let everyone talk from the beginning. It also makes sense given the backstory of the game. Actual diplomatic treaties would probably have to be sending an offer on one turn and having it accepted or rejected the next turn.Should there be any diplomatic actions that need to be researched?
I can't think of any that would require it, but there might be some far out idea that would make sense.Lasting trade pacts - Should these even exist? How would they work?
My concern is that they seem to have little downsides and are thus, not a choice. Why wouldn't I want to engage in trade treaties with everyone I'm not at war with?Research pacts - Some games have had the idea of allowing two players to enter a research treaty that allows them to both get a 10% bonus to their research or something.
One time trade deals- These are the staple of trading in almost every game. I give you X and you give me Y. Should there be items you can't trade?
Can I trade 5 wheat, two militia guys, and a tech for a planet?Tech trading -
I am highly against tech trading in general because it is a huge rich get richer mechanism. New tech means that you spend that first turn trading it to everyone you can. If you're late to research a tech not only are you already behind, but you probably can't trade it to anyone, which means you're even more behind. A middle ground on this issue is to use a system called "No tech brokering" where you can only trade tech you have researched yourself.
Another option I kind of like is to disallow tech trading, but instead allow treaties that temporarily give access to certain tech. You piss off your braniac friend and he'll pull out of the deal and you can't build those dark matter tanks or whatever. Similarly, just being able to buy units from people with better tech seems to fit theme of secrecy and proprietary tech that this universe has.Bounties - Described in the design docs, someone secretly places a universe wide bounty on a player and anyone who damages that player gets money withdrawn from this pot dependent on the amount of damage done. Games like sins of a solar empire even had a neutral faction that would attack the player with the highest bounty to shake things up.
Contracts - Not a well developed idea yet, but it would essentially be an agreement for future action that would actually be enforceable by the game code and not just a verbal agreement.
United Nations Type Mechanics (Bidding/Pooling) - To bring players together a bit more I've developed some ideas that really force a lot of player interactions. If you are interested in something like this I wrote a treatise on the subject using some unique ideas at
http://forums.elementalgame.com/374818