I know it's a bit early to be discussing diplomacy models, being a 0.5 topic, rather then a 0.4 topic, but I've been wondering about how to make a multi empire governing body and wanted to post my ideas.
IMO 4x multi government models tend to suck. SMAC's annual council wasn't powerful enough *I've played full games of SMAC without caring about a single council outcome*. MOO2 had a council only to enable Diplomatic victory. GC's 'United planets', although occasionally meaningful, is far too random. . . . . and many other examples.
A two tiered full diplomacy model allowing for non game ending surrenders, Post/Pre war neutral zones, an intergalactic court, mutual defense armies, arms races/smuggling, karmic polarizing galactic wars, less probable states of never ending war, and greater emphasis on 'alternative' victory methods(alternative to blow everybody to smithereens).
In this model two semi-disconnected tiers of diplomacy would exist.
The primary diplomacy would be two races/governments making trades, establishing trade routes, exchanging information and doing most of the things which most every 4x game has to a greater or lesser extent.
The secondary level would become active when two or more races sign non aggression pacts -> mutual protection pacts-> shared attack plans -> alliances -> ect, or after one or more groups surrender to another group or groups.
Since I tend to be wordy, and since the first level is mostly self explanatory I'll not explain it any more then to say most anything two races do diplomatically, which doesn't directly involve any other race would be done at the first level.
The second level would be a UN-esqu governing body, but critically this body would not include all races, and there might (probably will) be more then one of these active at any given time.
The task of the second level would depend on agreement signed,
non aggression pact -> establish neutral zones, and establish a court for punishing infractions (the guilty could then chose to accept or reject the courts decision, with obvious consequences) [meetings would discuss/move boundaries or change infraction penalties].
Mutual protection pact -> With the mutual protection pact, comes big departures from other 4x games. The second level diplomatic entity would be an ARMED force with space vessels of it's own used for patrol of high risk borders.
This level would establish a diplomatic council, with members from races in the agreement. Votes would determined by how much money/resources each group puts in. #votes = total_investment(money, pp's, ect)*(% of total available income money/pp's) [On a slider you would invest a number of pp's and an amount of money, and it would tell you how many votes you earn that turn. Both the % of total income, and the absolute amount of resources donated would be used to calculate votes].
The diplomatic council would be concerned with such questions as 'which boarders to patrol the most', any 'collective spy' efforts, 'additional trade pacts between the governing body and other entities', and start to have questions similar to those seen in other 4x games see 'http://galciv.wikia.com/wiki/United_Planets_issues' for a list of possible examples. This level of council would meet periodically, but the questions would not be random, instead every second meeting would be a vote on which question to discuss, conclude on next meeting. (meeting one, what question for meeting 2, vote for favorite from a list of possible questions, pause of several turns[try to 'win' other races to your desired outcome in the first level diplomacy screen], pose question and vote, receive list of what questions will be for meeting 3, try to 'win' other races to voting to discus your preferred question).
Ships for this governing body would be constructed at idle space docs of races in the agreement, using the money, pp's(from vote buys), and best available techs from each race.
If ships from this governing body engage enemies ships would be temporally assigned under the control of constituent members for the duration of the battle [how to allocate??]
shared attack plans -> The council would need a leading figure, or leading race, votes for which race to chair the council would be added to regular routine of questions. [Benefits for being leader? spy bonus? veto? occasionally able to choose question without consulting rest of members?] Question list would be expanded to include war plans(simplified to attack along this boarder, or from this star lane), and mutual research efforts.
alliances -> Might be just more questions . .. might not be needed, just move all of shared attack plans to alliances and call it done.
The only remaining thing is Non game ending surrenders. In most 4x games, surrender means game loss for surrendering empire. Essentially surrender is only there to sometimes prevent the need to individually concur every colonized planet.
IMO surrendering should be a valid tactical move. You can still win the game having surrendered during the course of it. Surrender would be a diplomatic trade option during wartimes, where both sides would 'barter' over the definition of neutral zones, and compensation fees. Since the only reason to not accept a surrender from an opponent is because you want to concur the whole map eventually . . . not reaching a mutually acceptable surrender agreement would 'Significantly' hurt relations with all other races.
Note; War's have reasons (even if they are fake) those 'reasons' 'may' include the 'need' to expand borders. But since expanding is politically dangerous [makes you look much more aggressive, therefor a bigger threat to all] it should not be unusual for the surrendering empire to actually re-claim planets lost to the aggressor during the war. Say Empire A destroys 60% of Empire B's standing army and captures a long string of planets to Empire B's capital + some border planets, then Empire B surrenders. The model should in most cases would build a neutral zone out of 'most' of the border territories 'with usual political unrest in neutral zones, rebels freedom fighters, terrorists on both sides, small interplanetary military [and unofficial] skirmishes (which both sides can illegally aid with arms smuggling)'. The long string of planets leading to Empire B's capital would be returned to Empire B, and only a few of the planets/systems nearest to Empire A would be permanently included in Empire A. This would significantly reduce the emphasis on military victory since anything short of one race against the combined forces of the rest of the universe would result in minimal territory expansions.
Ok, once against, I've written way too much . . . My apologies to your tired eyes.
I'd love to hear any ideas on this model or similar models, + how to flesh out / better define some of the components.
Best wishes all