Proposed solutions: 1. Keep the balance of players connected nation in real time, allowing only until an acceptable margin. Harmful to the game because the player will feel not allowed to play. 2. The fewer players registered have a nation, the greater the reward in gold and experience in fighting. In turn, players registered in a nation with a large population get very little gold and combat experience. Note: This alternative would not solve the problem by itself, because, what good is defending a port with 5 "Santisima Trinidad" vs 25 "Trincomale", "Constitution", etc? 3. create a system captured ports, where players from that nation, have the obligation to maintain a commercial logistics (deliver demanded products) to keep that port for your country, then the ports that do not receive such products, after "n" days becomes a neutral faction. Smaller nations = demand is small and "n" will be greater. Factions most populous = demand is higher and "n" will be smaller.
Fix this problem is urgent for a balance in the open world, but some factions will be reduced to 1 port on the map soon. This should be a priority for you developers.
Note: courtesy of google translator, so excuse my English