I want more vassal control (which also leads into why I want more new world civs, e.g. ex colonies) in the game. I think there should be different kinds of vassals. Ones where you control their forign policy (what techs they can trade and to who, resources, open borders, civics, etc.) to where you have little control (like it is now). I think it would make the game more interesting and you wouldn't have to worry about your bone-head vassal trading away all your precious technology.