[Skimmy2]

I think that I would rather try to do what I can to make the world more interested in interacting as a whole first (not to say that I'm against the ideas presented, nor that I won't do anything mechanical on a smaller scale until then). I'm still developing my ideas on how to accomplish this, but I think that the game itself could do a better job of supporting such things mechanically. Ultimately interactions with other nations are just fluff, even within your own nation the things your character is supposed to do are limited by RP situations happening that let them do their job.

I don't think it's something that systems can entirely solve but I do think, for example, making interactions between nations less based on fluff has more of a recurrent, long term benefit. The same could be said for balancing 'things happening because someone wanted to make them happen' and 'things happening because of something someone else did' a bit more evenly. Sometimes circumstances need a good shake up, sometimes relationships need a tangible reason to change; and sometimes that needs to happen from the 'DM' level.

I'm not sure if it's something I can accomplish, but it's something that I've been thinking more and more about lately.

There's been a lot of other interesting things said in the thread that I agree with, but I'm nap bound for the moment.

In regards to adding Mechanic based interactions. (And solidifying the permanent nations that Korvara revolves around.)
You'd be surprised at how easy it is to spark conflict, dialogue, and interaction by simply adding resources/MacGuffins that must be contested and vied over.

As an example, currently map requests may cost an amount of LegallyDistinctMurai or possibly materials by a Player. Imagine if your Nation also required X number of resources, say "2 Lumber". Now your Nation (and you the Player) have a vested interest in securing X Resources for X amount of Time so that you may have X Built in game.

Taken another way, It is well established that Geladyian land is hurting for food to munch on; and while it's established decently enough through roleplay and lore, actually adding "Food" as a National resource does wonders to set the scene. As an example, say Geladyne produces 5 Units of Food, but requires 10 Units of Food or X will happen. (Roleplayed bad things, or if mechanically needed, something as mundane as NPC Shop prices increasing or resting at Inns healing only a fraction as munch).
Now the Geladyne leader and to an extent, it's players have a vested interest in somehow securing those extra 5 Units of Food, whether diplomatically or otherwise.
Throw in resource scarcity, such as each Nation requiring 10 Food, but Korvara only having 38ish to go around; and suddenly the land isint the peaceful paradise that it is trending to be.

This, of course, is not to say that we need to turn SL2 into a 4x strategy game mind you. You yourself seem to have some of your own ideas bouncing around in your head; whatever that you decide upon, don't be surprised at what can be accomplished by simply dangling a carrot above our heads.