Right now, it is often frustrating that when being in an alliance with ai players, these either just declare war themselves in inopportune moments, or make truces shortly before you can finish that enemy off. 


This leads to the problem that often just being in an alliance is more annoying than helpful due to the constant hold-ups this poses.


Additionally, it doesnt really help with immersion when the members of the alliance have no real interaction with each other about such major decisions.


So:


  1. implement a system in which members of the alliance can vote on declaring war/negotiating a truth...etc
  2. each member`s weight on the decision is dependent on its importance in the alliance (no. of systems, influence output, military strength relative to the total strength of the alliance)

example: 

My empire holds 40% of the alliances total military strength in the alliance, the other two each 30%.


i propose declaring war, and with 40% of the military strength i hold 4 out of 10 seats in the alliances "military council" or whatever you might want to call it , the other two hold 3 seats respectively. 

i need a majority in the council to get the vote through, so it would be enough for one of the other guys to agree with me


This would make alliances more lively, and also allow for the existence of alliances dominated by one strong member or a very democratic alliance of equals.


Furthermore, one could include more diplomatic options by convincing alliance members "on the side" to vote for ones proposals in the alliance council.