National Specialization Laws:
Laws that can specialize a nation's choice of trade and military orientation, to give a diverse option of different nations truly based on wieghed choice rather than the current pick-something-from-the-box type, could be useful in the game.
I have a few Ideas, just some of them.
1)Unique resources of nations: While ports do control what is to be produced most of the time, the people of a nation are not limited to it, by any means. What I mean to say is that a nation should have a special resource for itself with which it can extend its operations in trade through deeper grasp on the economy. If a nations is specialized in wood, then all ship costs, wood-industries, buildings should cost less. And, if the coming time allows the player production of wood, then special previleges with those should be allowed too.
2)These are to be chosen by a Nation. It can be chosen each time a new King/Queen arises. Laws relating to this, if passed, change the outlook of the nation. Currently, you get a spike of excitement on seeing a new-flag on the map, but fall back, because most people didn't have a thing involved with it. Besides, that spike of curiouity fades away as soon as you get off the map. But if such laws are here, then it would become really necessary to check out what the nation is specialized in, for it will affect the produce of the port(s) which changed hands.
3) When ports change hands, they create ripples in the whole world, not just the nation that captured it. I suggest that the policies oif the nations affect the port to such an extent that players will also experience a few benefits of having the nation on map, along with a few disadvantages, regardless of the nation they are in, even if they are not of the nation that captued the port (I mean, an capture is a global event; it should affect everyone globally, not just the members of one nation)