I've seen the mess going on in Kuwait after their ruler died. At this end, I will propose a fool proof system that can be used in the GCC and any other clan government around this nice blue planet. It is more of a balanced score card approach.
First of all, gather all the people that have a family name thats similar to the late king/amir/papa smurf... whatever. Then, play a big game of musical chairs... preferably in the cabinet of ministers, since lots of folks will get seats over there as consolation prizes anyway.. with whats left.. thin out anyone under 60 and without facial hair around the mouth for some reason.. now this is the smart part.. put them through a physical test.. see how fast they can walk on a red carpet from the rolls royce to the airplane, how steady they can wave their hand at delegates, and how much hand-shaking stamina to recieve nose kissers on different occasions.
Choose the top 3.. and the grand winner is the person that has the nicest signature.
PS: Isn't it funny that in bruital Israel, no one assumed power or made speeches on behalf of other people when the prime minister was in the hospital? Checks and balances or balanced score card?