Hello.
Just a minor suggestion: Could the individual cultures have simple, stylised emblems that player characters could use to tell them apart quickly ?
I think the fact that the game portrays the cultures in a more anonymous way at the moment, largely through their lifestyles and the tools they use, is actually better for immersion purposes.
Furthermore, given that this is a late Iron Age civilization, with more scattered populations, no real towns, no cities whatsoever, no stone structures and institutions yet, no nobility or peasants/serfs, etc., that it is good the individual cultures do not have any flags or coats of arms or more standardized symbols. Again, it's better for verisimilitude and immersion.
All the above said, I still think it could be beneficial for gameplay purposes if a few menus occassionally featured a simple, stylized emblem that would represent one of the 9 (10 ?) cultures. For example, the northern tribes would have a silhouette/outline of their totemic animal, from which they derive their monikers. The other cultures could have simple emblems that would reflect their typical economic and cultural strengths, and so on. Due to the more primordial feel of the setting, I think the background texture of these emblems could imply they are painted onto or burnt onto a decorative piece of leather, or painted on a smooth enough piece of bark (specifically, the inner side of the bark).
Why would emblems be needed ? Because, as much as I like that more anonymous approach, sometimes I wish I could just look at a conversation screen and see that the other character has more than just a boring text description there, saying they are from this or that culture. Ergo, I would find it nice if they also had a little emblem representing what culture they are from, situated in some empty part of the conversation screen.
I think a game mechanic that should stay in place is that an unknown individual or unknown village would not have its corresponding culture's emblem shown to the player until he or she met with them, they introduced each other, and gained at least some basic familiarity. Then it would appear somewhere in the corner when talking with an individual. It would also not appear in the player character menu, other than the player overview screen, showing the stats. The fact that the characters already have "surnames" based on which culture their character belongs to is more than enough during usual gameplay.
Finally, I feel that different simple emblems could give the cultures further distinct personalities, beyond what in-game behaviour patterns they use while creating their settlements, or hunting or trading, etc.
Just a thought.