Hold more Duchies
Have you ever felt that a great emperor like you could hold more than just 2 pathetic duchies? Especially when your holdings occupy half a kingdom? Are you tired of envious vassals who keep annoying you about one extra duchy title you hold? Ever wanted to become a captain of a mercenary band but, alas, vassals are outraged by "TOO MANY HELD DUCHIES"?
Forget about it. Now you can hold 6 duchies at the same time, which means that you can comfortably manage your demense size and duchies amount. Or perhaps you want to lead your own mercenary company and be a king at the same time? Not a problem anymore.