(1) Get rid of the ones which are in the same spot on a real map (Turks/Ottomans and the Byzantine Empire)
(2) Get rid of the civs which are already represented in the game as it is (Byzantine is represented by the Romans; Olmec are represented by the Aztec)
(3)Get rid of any 'civilisation' which did not have any cities (i.e. Neanderthals) sp?
(4) Get rid of civs with little or no impact (Califonians)
(5) Vote for civs where there arnt any. For example Europe has plenty of civs, but there is a huge enpty space in Asia where the Mongols could fit, in Oceania where the Polyneisans can fit, and in the Americas where the Incas can fit. And in Africa, vote for the Carthagenians.
Talk about vote influencing.