The KotR system was simple: the Emperor gets the provinces and hands them out as he pleases, though once given to a House they cannot be taken back without war. This worked fine in the game, though I do recall the people playing the Kaiser handing them out rather evenly instead of exploiting the system for partisan benefits. Since paritsan play by the King may be more likely in the new game (it was specifically stated in the KotR rules that it should not occur there), it makes sense to allow for an alternate route around the King. This fits historically as well, since the French Kings were pretty weak in 1080 AD and took a long time to consolidate their power. The simplest solution is to allow a 'Council of Nobles' vote to override the King. If the King allocates a province and a Duke protests this allocation, a Council of Nobles vote is called and can veto the allocation by a 2/3 vote. The Nobles can't pick WHO gets the provinces, but they can block it until the King gives it to someone they approve of.