trade agreementsystem
How about introducing a new trade agreement system.
Introduce an option to create an agreement (1 week, 2 week, 1 month...)between two nations for importing and exporting their resourses
Lets say nation1 and nation2
Nation 1 has high amt of food and nation2 dont have food but oil.
nation1 contacts nation2 for an agreement over importing oil for food. There must me options in this system.
example : nation1 gives an offer - 20% of the the food produced in every turn will be given to nation
Instead of doing automated agreements (which put a big load on the server) you could instead find the nation you want to import oil regularly from, have him send you a big personal offer (like 500 oil at X price) and then just accept the offer in little chunks as you need it.