It would be cool if you could bring back lost cultures through special events, an example would be Etruscan since it the culture was the basis for Tuscan culture and the Tuscan Area is neatly packaged already. A way to bring back lost cultures would be to control the entire modern culture, then to build a university or some other special structure. Still not entirely sure how it would work, but the end result would allow the player to form a special nation like Babylonia or a Rome with out the conquests. It would be Empire level and have increased reduced conversion costs for the rest of the cultures in the starting culture group. An example of something more complex would be Phoceian which would require the Northern Levant, Tunis, Sardina, and Sicily. While less complex cultures would be Spartan or Athenian. Both of which could be revived by taking a simple mission to rebuild Sparta. The main idea with these is to provide a way to empower some nations in this region that are usually overpowered by larger nations.