I have posted quite a few suggestions for a pirates overhaul which I believe fit in the 'Diplomacy' theme:
https://forums.sinsofasolarempire.com/351529
About the diplomacy with gaming factions, though, I haven't said anything.
I will tell my ideas even if they have already been said, you should want to gauge the popularity of the ideas:
One capital per star system. It could be researchable, and not as effective as the 'Empire Capital'.
Change culture/allegiance mechanics. Culture should have consequences according to the relationship with the empire associated. I should be able to notice not only how much of my culture, but all other cultures in each of my planets as well. 'Corruption' counts as a culture too, and benefits mercenaries / pirates (see linked post above).
Stances against each other empire. I should be able to set my stance as 'At war', 'Armistice' or 'Peace Treaty'.
If player A has a strong culture, it will influence player B's neighbouring planets. If they go to war, the amount of player A's culture in player B's planets will degrade ship production and credits/metal/crystal generation. An armistice would reduce the penalty by 50%. Peace can give an economic bonus depending on the amount of time the peace has been kept and the standing of each race towards the other.
Neutral planets would all be considered 'minor factions'. Minor factions can be either race, or independent 'rogues', runaway from the main races, in which case the ships in the gravity well are mixed between races. Their stance against ships inside their gravity well would also be varied. They could be friendly (peace), neutral (armistice) or aggressive (at war).
Planet domination would be possible by culture. Having a large majority (say 80%) of the planet's culture (be it an opponent empire or neutral faction) and trade and military alliances (more on those later), you may offer something in return for their vassalage. It would work by oferring something in the Diplomacy screen. You will be bribing the planet governor when you ask him to switch to your empire though, so expect a sharp drop in diplomatic relations to the offended party, as well as a probable attempt of military re-occupation.
In the case of a cultural takeover, the offended party has a time frame where it can break any agreements without penalties, and declare war with very little change to its 'Warmonger' trait.
The Diplomacy Screen
One should be able to engage diplomacy with other empires/pirates, and do one of the following:
- Trade goods
- Instance trade - goods trade hand one time, like when you buy on current black market
- Trade either goods or information obtained by scouts or espionage
- Can make a complete trade proposal and ask if the other party agrees i.e. 1000 credits for 200 metal
- The other party can accept or counter-offer
- Can make a partial proposal - I offer 1000 credits for metal - how much do you give me?
- Accept/request missions from/to a specific Empire
- Combat missions
- kill X ships from player C
- kill frigate factory on planet Z
- scout planet M
- help me attack player C
- help me defend planet M
- Diplomatic missions
- Trade agreements - trade X credits for Y metal for Z minutes
- Trade alliance - increases income, especially on planets with mixed culture
- Military alliance - increases military strenght perceived by other Empires (influences diplomacy) and allow buying ships from other empire at greater cost if same race, or much greater cost if from different race
- Declare war on player Y
- Trade embargo player Y
- Request vassalage (other empire surrenders to you, giving control of all planets) - not possible against pirates
- Mixing different races this way would have an impact on economy due to cultural clashes.
- Building stuff from the vassal race (if not the same) would have a cost multiplier.
- Some research technology would mitigate the penalties.
- Demand tribute
- Like the above actions, but offering nothing in return
- Offer gifts
- Like the above actions but ask nothing in return
The culture from dead or surrendered empires and factions should keep going even after they are dead, and getting rid of it would take time. If a vassal culture drops below a certain level, the knowledge of their machinery is lost and they can be no longer operated i.e. frigate factories , tactical defenses, ships etc. stop working.
Each empire would have several traits which would build up over time, as the game progresses.
Although the traits are local i.e. each empire sees the other by its own light, your actions against/toward one empire may influence how the others see you.
Friendly / Arrogant - Dpends on whwther the player sends gifts/makes demands, trades at a loss, bargains hard or makes outrageous proposals to other empires / pirates
Trustworthy/Backstabber - Do you keep your word? Are armistices respected? When some ally asks for your help, do you help him? Do you backstab allies and invade their planets? Do you deal with pirates? Do you secretly asks for someone to attack your ally? Backstabbing allies should have the greatest impact against trust. Negotiations with any empire/faction shoud be secret, but espionage should uncover the 'dirty secrets' of what you may have done.
Peaceful/Warmonger - Do you prefer to colonize other planets by culture or by force? Empires which declare war always rise their Warmonger trait.
Dominator/Eradicator - Do you call witch hunts to eradicate dissents from your planets? Doy you siege bombard enemy planets until the enemies are all but exterminated to then colonize (Eradicator)? Or do you prefer to se occupation forces to take over the planets without wiping out enemy population, thus culture and initial income (Dominator)?
Vasari tend to be Warmongers and Dominators, while Advent gravitate towards peaceful (well not quite) and Eradicators. TEC would be more Peaceful / Dominators. When the game begins, the AI would be internally set to have a variable tendency to do actions towards one or another, or sit in between, but the perception of the empire would depend on the actions which would happen during the game history.
Military, cultural and economic strength all would weight in when attempting any kind of trade. Prematurely breaking agreements would give a negative bonus.
Instead of sieging a planet, one should be able to send occupation forces to the planet surface. This could be a siege ship ability which consumes the ship. Depending on the planet strength - number of upgrades - more siege ships are needed to occupy it. Some of the population would die (50% maybe) , but it would not be as bad as completely wiping out the planet. Planetary orbital structures would be retained and switch sides to the dominating player. On the defending side, friendly siege ships can send troopers to the surface to restore the resistance against the invaders.
Espionage missions could be performed. Scouts have a researchable tech where it can be 'transformed' (disguised) as a scout from another faction. It can then go in a gravity well from another faction. If the scout uses any tech except the 'plant spy' it will be detected and acted upon accordingly. This action consumes the scout. Scouts will also have the 'detect spy' ability, which they can cast on other scouts, planets, structures or ships. Detected spies will be killed, and may or may not confess who they work for. If they tell which empire they are from, relations will deteriorate.
Several spies can be stacked on the same place to increase effect.
Spies will have different actions accoring to where they are:
Spies on the planet can:
Initiate propaganda on behalf of your empire, improving your culture there.
Make terrorist acts, killing part of the population. Can 'always work' and kill the spy, or have a chance of failu in exchange of having the spy survive. The latter may fail and kill the spy.
Divert economic resources to your empire. Will 'improve' corruption in target planet.
Sabotage planetary improvements. Same as terrorist acts.
Attempt to kill the governor, temporarily stopping production/income. Always has a chance of failure.
Although this one is not Diplomacy related, fleet should have a 'space-wave resonation' tech, which would increase the fleet's velocity and turning speed. Fleets really needs to have a speed boost to be more useful.
Maybe more fleet-specific improvements could be in place too, race dependent. Advent would have 'shield resonation', which would have a small percentage of the damage to be distributed to other ship's shields, thus improving any individual ship's survivability. TEC would have improved repair speed, while vasari would have reduced weapon cooldown.
And more techs! I like big tech trees. The diplomacy stance alone would be enough to warrant a few techs. The above Fleet enhancements too. I wouldn't mind having 10 tech levels or more, even if it means getting the ultimate techs less often. One hardly even researches any level 8 tech in a small map anyway. Higher level techs should be for bigger maps, and long tech trees give that sense of grandiosity .