You should really get rid of the Grad title function. It is not realistic and you can usually get claims through marriage and events. One area that could be improved; when a vassal rebels, there should be a victory function which forces the former vassal back into his vassalage. This is what historically happened. You should also have an option which puts the vassal under the ban, and forfeits his personal lands and titles to the Lord or his allied victors. Of course, in the case of rebellions - foreign allies should not be required to assist in the fight.
Oh, one other thing...The real problem with the grab function is that the human player can exploit it and conquer the world in about a hundred years eliminating the purpose of the game - to revisit the Middle Ages.
Oh, one other thing...The real problem with the grab function is that the human player can exploit it and conquer the world in about a hundred years eliminating the purpose of the game - to revisit the Middle Ages.