There really is no way of changing the game to reflect this more except to get people from these countries and put them on the teams.
The economy is the most real aspect of this game. Though it does fail to address a few aspects of the real world. One, countries trade with other countries, there are no open markets for everyone to buy and sell from. Second, the companies within the countries set the market price. Usually, companies in the same industry ban together to make sure prices do not fall to far down, and example of this is OPEC. .
Never has a country stated its intentions and shown the world the exact placement of its navy and armies. With the board in plain sight of all nations to see you can make a very good educated guess at where people are going to attack because you can watch their army build up. Granted there are spy satellites nowadays to keep track of that stuff, but armies can still sneak around with the cover of night and totally surprise another nation. I think that after the initial armies are placed on the bored each country has the right to show everyone else where their armies are or to right them down and not place the armies on the board so only the country and the people it deems necessary to know, know where an army build up is taking place. .
This should especially work for navies because it's hard to locate ships out in the middle of the ocean unless you know where to look for them at. An amphibious assault was impossible in the game because the country would see it coming with enough moves left to build up forces of the coastal areas. Navies should be hidden until ships enter the same see at which point both sides ships become visible to each other and everyone else because they are in range of seeing each other.
The biggest handicap for the game, which is a strength for almost every nation in the world, is the air force. The air force is a vital piece of the military because it can inflict damage on an enemy without the commitment of ground troops.