I can hardly even begin to explain the awesomeness that this would be. And it should be added to fiefs as well, so that "message" is directed to the fief owner.
Diplomacy should not be on forums, after all. Highly public diplomatic efforts just aren't realistic. Diplomacy should be a closed-doors thing.
And THEEEEEN...
Incorporate rules regarding the tradition of medieval signet rings and "seals".
Each player has the option to:
Write unsealed, unsigned.
Write signed but unsealed.
Write signed and sealed.
So, basically, it would be against the rules of Strat to "fake" a seal... but scrupulous lords might very well decide to send their sensitive correspondence with merely a signature, as some verification of authenticity. And for the REALLY dirty stuff, you can just send unsealed and unsigned notes.
This system could be done by emoticons/*ActionText*/[ExplanationText] or by an official system where the message has a little .jpg image of a signature and/or seal depending on the delivery method (if the devs wanted to take the time to implement that much).
Anonymous correspondence would be a cool addition too.
Why bother?
Strategus is not a game about battles. Strategus is a game of politics in its many forms: ideological competition, economic security, personal rivalries, vengeance, trust, fear, etc. Anything that promotes that political aspect improves the game more than +1 damage and -2 speed on greatswords (that are rarely used in Strat until late game anyways) ever will.
