Game is so much fun :D
Reminded me of my WorldBox worlds when all of the land was occupied by kingdoms.
So I have a few ideas for the game:
1- If you are going to make alliances, make them have names or something that identifies them (I mean alliances like a group of nations, not an alliance of relationship between 2 nations) and that when an alliance wins a war against another allience, all of the captured land will be shared equally between all of the nations of that alliance.
2- Nation traits (Like the ideology idea of MewsterGames). This will be like the nature of the nations, for example:
-Aggresive
-Peaceful
-Rich
-Powerful, etc.
So you can make the nations more unique.
3- Tecnologies. A tecnology tree that you can see when you see a nation's info. Nations will be researching more and more over time, and some tecnologies only unclock when the world reachs a certain age or era. (You can also add this, for example: Stone Age, Bronze Age, Medieval Age, etc.) It will be cool to have distinct brands on the tech tree and that nations develop their own style, for example: Army and Economy, Colonization and Politics, Relationships and Army, etc.
4- Army raids. This could add more use to the Armies tabs, basically its that the armies move around the map in big groups (It can be sea or land, also sea ones could transport land armies) and fight each other.
5- Distinct types of war. There could be different types of roles in wars, for example: One nation declares war to another, that nation is in the role of "Attack", while the other, depending on their traits and the situation, could be "Defense", and hold still until peace, or be "Fight Back" and try to fight back the enemies while conquering their land.
6- Recources. Not only land, resources can make the difference in a war. Things like gold, food or soldiers will do.
7- Trade. Nations/Alliances can make trade routes and trade resources with other nations/alliances.
8- Cities. Besides of the capital and the forts, this ones would be strategic points for nations and alliances, because they will produce gold, soldiers, and serve as trade points.
9- Nations don't disappear when their capital has been taken. Okay, some will, but what I say is: There was one nation that has the entire Africa, and then *poof*, it disappears because their capital in Madagascar was taken, its just too unrealistic. You could take the city mechanic I sugested and make that when a nation looses its capital, it just switches to another city, but with a HUGE penalization (Land, resources, whatever you want).
10- Time go slower/faster. Sometimes I would like to slow down time to see what happens with detail, and sometimes I just want to go fast foward. I don't think that I have to explain this one.
11- Slower colonization. One single nation that started on a small island colonizated the entire world with insane speeds. Maybe you could make that colonization speed depends on size, resources and tecnologies of a nation.
12- World peace. Wars cannot occur just because, you need to justify that with something, it could be hate, alliance, or something else (Maybe nations that go in several wars become more hated, and peaceful ones don't get wars almost never, they are more protected and only be attacked by war-based nations), its just that world never achieves real peace, like our world today, maybe in some point of the game you could make this happens. (To keep the fun in this state, nations can still make small wars sometimes, or WORLD WARS.)
13- More player interaction. Maybe make the player able to moddify relationships, alliances, thecnologies, resources, wars, rebelions, or basically everything on the game (Like a God Mode).
I know that what Im asking for is A LOT of work for you, but if you could take the time to make this, not even all, maybe just one or two, I would be happy to come back and play with these new features. I just want to say, that this is an awesome game with an awesome future, thank you for reading this ;3
PD: LONG LIVE TO MINORNIA!!!!