After playing a game of Diplomacy I was thinking that there should be a new map where water is a territory. This would be specifically best for a full world map such as classic or world 2.0 because water is 70% of the globe.
This would make continents a lot harder to keep because you can be attacked from the water and would make the game much more defensive and once a person has a number of bonuses and a set of cards the game is not basically over because they know that they need to fortify all their borders.
The water could be broken up into oceans with the atlantic and pacific broken into north and south. I dont think that the water however should be a bonus because if you hold all the water you will win anyways.