Technology isn't the only thing that evolved throughout the ages. I have looked around for Neolithic sims coming out and I have seen a huge focus on base building, but not so much on other aspects of society like religion, art, and music. If this game is to stand out from the crowd of other RTS and city-builder games, having the culture develop with the people would be a real seller. It would be so cool to see my group of humans go into a cave and start drawing animals, or developing a writing system. It sounds like a lot, but I truly think the pay-off would be tremendous.