Peace Treaties
Personally I think there should be a minimum number of turns that you can't go to war with someone after you sign a peace treaty. If you DO declare war before this time period is up I think your diplomacy rating should be pretty badly beaten.
Agreed, this would be nice.
Resource Treaties
Imagine if you could LOAN developed resources to other races? That would REALLY allow you to make a big contribution to someone elses war. You could loan them for a certain amount of time and then they would revert back to you at the end of that time. This also adds a neat twist. If I am neutral to A but at war with B what do I do when I find a starbase that is lending resources to A? If I destroy it then I am at war with B. How do you prevent exploits (i.e. get a deal to loan a race resources before declaring war). Well, it could either be assumed that a third party would be running the starbase so its still not yours until the end of the contracted time, or you could simply savage the scoundrel's diplomacy rating on all races. I suppose a Resource Treaty indicator could be part of the Treaty Screen, and some sort of indicator on the actual starbases showing who it is being leant to and for how long if your espionage is high enough.
Being able to loan the resources from Mining Starbases would be an incredible diplomatic option. I
really think this should be considered to be added to the game in some expansion, whether this one or not. Certainly, there are risks of "increase the value of my trade before I declare war" exploits... but you can already do that with the current Economic/Research treaties.
Espionage Treaties
Signing such a treaty automatically grants Low Espionage level to each of the signers. In addition for a small, ongoing fee you share a small amount of espionage on other races that you gather. So even if I am not spying on the Drath I get a percentage of Intelligence that the Humans are gathering on the Drath.
This would be pretty nifty too. Of course, I'd rather see them bring back the DL slider system of Espionage Intel Gathering back as the
main (agents can help) source of intel gathering and leave the current DA Espionage Agents solely as sabotage first, though.
As it is currently, agents are too expensive to try to use them to gather intel on races, imho. I've never get more than Medium Intel Level on a race (and even that's rare) in any of my DA games, but my DL games, I always had High level with ALL races...
Vassal States
I never go for a military victory since it takes too long to do all of the mopping up, and its just not fun IMHO. I think it would be cool if you could force a race to become a Vassal (or offer to become one if you are being hammered). A Vassal turns over all resource bases, and can only trade with the controlling race. In addition they are unable to declare war or peace, and are automatically at war/peace with whoever is the controlling race and vice versa. The relations they have with all other races mirror the Controlling race's relations. Now if the Controlling race declares war on a Vassal their diplomacy is thoroughly savaged.
Now at an opportune time, or if the vassal feels it is strong enough to through off the chains of oppression, then they may break their vassalage. All wars that they were involved in cease and their relations to all other races are neutral modified with how that related race feels about the controlling race. Of course breaking such a vassalage is an act of war to the Controlling Race.
I'd LOVE to see something like this brought in as a replacement for (or in addition to) the current Surrendering system.