Also could we get the ability to join non-military alliances too? And then I think the best additions to the game would be things that can only be done as certain countries, to improve replayability. Either arbitrary achievements, or country formations, or both. For achievements you could look to paradox games' achievements for inspiration. For country formations, I think this page works well: List of proposed state mergers - Wikipedia. In general I think deeper diplomacy with a specific other country through a dedicated window would be good. Also probably landlocked countries shouldn't be able to go to war with countries they don't border?