It's a nice idea, but it more suited to a 'diplomacy' kind of game, like Crusader Kings. MTW's diplomacy system is broken anyway. MTW is, for all intents and purposes, a battlefield simulator. Outside of the battlefield, the game is rather rudimentary. I don't know how RTW would do it, though.

However, it is unlikely that it will be added, since it is a relativily unimportant part of the game. The CA team will probably work on more important features (like bugs, sea battles, or refining the game). Adding new, little used features to prolong the game if the player fails is probably not high on their priority list.