I like the Vassal and Liege system, except for one thing. When you conquered a city and the player becomes your vassal. He/She can simply declare War on you, and isn't your Vassal anymore. You basically take the effort to make an army, travel to the destination and probably having to take over some unwanted territories in the process ( EP going down the drain) , battle your enemy... You win, the other player becomes your vassal, and then with only one click, he declares war on you, and isn't your vassal anymore. You end up gaining nothing ,and you were punished for making an effort. The other player has nothing to lose, not even a single unit since he can just transfer them to its general and go away, and come back afterward.
Solution : If the Vassal declares war on his Liege, he stays as a Vassal until he conquers the Liege himself.
Any thoughts on that ? Or is it just me.