I've played through probably a dozen EB campaigns, as well as a few other mods, and check these forums and the twitter regularly just to keep track of my favorite mod, but I really never post (mostly because I don't really do forums, and because I would end up getting in innumerable arguments about interpretations of history). There has been one point that keeps coming to mind when playing EB, and other mods: generally the vassal state diplomatic actions are ignored.

I understand that in EB the government types fill the role of vassal cities. Additionally I understand that diplomacy was not easily manageable in RTW, as far as controlling AI diplomacy anyways, is this different in MTW?

I would love to see an actually useful implementation of vassal states in EB2, or another mod. I think it would add some realism to the game, being useful to exemplify the autonomy of regions of empires (I.E.- Rome in its control of frontier regions). This would result in the much more common diplomatic action of defeating a nation and then taking tribute and influencing their policies, rather than simply invading directly governing.

Another option would be to have a campaign nation start as a vassal, and have to break free (plenty of examples but what comes to mind is Macedonia influenced by Hannibal [though that was a particularly unsuccessful example]).

Anyways I hope to hear back if this is a reasonable possibility, or if its technically impossible.