One thing about the strategic AI that I would like to see improved is the way it picks which provices to attack and capture. After starting in the 1792 campaign and playing for 23 years , the map eventually became a checkerboard of provinces. Countries were starting wars and taking provinces far from their homelands.
In my game, Russia owned 2 or 3 provinces bordering France and a couple in Austria, while losing provinces in southern Russia to Turkey and provinces in the north to Sweden (me). Spain held all of southern France, and provinces in Austria, and even provinces in north western Russia. Turkey was one of the greatest odd balls. They managed to keep almost all of their home provinces, and they eventually owned Ireland, a province in north-western Germany, and one or two provinces in Austria, Prussia, and Poland. France and England were also fun to watch because over the years France took (and held) a province in southern England , while England invaded northern France and held provinces there. England also owned a landlocked province in southern Russia. By the end it was mayhem, every country owned a province or two all over the map but rarely did any more than 2 provinces ever touch.
I think the AI should make it their number 1 priority to restore their national borders, with a few surprise attacks programed in. I also do not think provinces that are cut-off from their country's homeland should be able to contribute to the economy as much as one that is connected, especially if they are surrounded by people who you are at war with.
Ideally, I would like to see the game make it more beneficial for players and the AI to expand the borders of their homeland, instead of grabing random provinces that are landlocked and deep in enemy territory.
just some thoughts.