Read your thread and it gave me some ideas so I might as well post them, albiet they are about where you could go with this in the future... Considering this is essentially set in the stone age, are you planning on including crafting? I should think pretty much everyone would learn how to make their own weapons, clothes and tent, as well as growing their hunting/foraging skills.
Flint quarries could be important locations worth fighting over, as would fruit rich forest, game rich plains, fish rich lakes etc. If all important locations were capturable and carried benefits it could add to the game.
Could survival of your environment be alot more fore-front as this is pre agricultural, I suppose suggesting that if there is a group of selected hunters within a tribe (depending on their culture), they have good days and bad days where everyone goes hungry, occaisionally people are killed by wild animal/disease/accident, so that population and supply are important to your fellow peoples survival.
Maybe if you do something dishonourable it is possible to be exiled, so you have to survive by yourself until you can win back their favour, or the favour of another tribe, probably through acts of bravery sometimes against the people who exiled you to show your loyalty.
Edit; I suppose these ideas would essentially need the ability to starve to death, and for the NPC's in the game too. If you don't manage to find anything to eat over a few days, points start coming off your stats.