So I love this game. I think the diplomacy is incredibly well done, and I love the fast-forward function. But there is one thing I'd like to see:
You see, it can be difficult to coordinate with my allies. It would be nice to be able to "share orders" with your allies, allowing them to see a certain sub that is scheduled for the future on their map. It'll make prediction and coordination way easier.
I get that this could make stabbing people in the back harder ("Why won't you share that order with me?"), so maybe you could add a "fake share order" function as well.