Summary: Currently all council members are able to contact their "peers." These consist of the respective council members for that same position from every other realm on the continent. My proposal is that this is expanded to allow Dukes to contact all of their peers on the continent.
Details: Add a new peers messaging group for Dukes only. (Note: Not Margraves, but only Dukes)
Benefits: Opens up many new avenues for communication and interaction between leading members of realms. Could lead to increased intrigue and cooperation and allows those outside of the realm council to better influence events. Will likely help counter stagnation as Dukes would no longer be dependent upon the realm council for communications with foreign realms. Would lead to more active and engaged Dukes and allows for both internal and external power struggles.
Possible Exploits: The only exploit is now being able to talk with those unable to before, and having an easy access to it. However, I can't think of any uses for this that are bad for the game.