Wingednosering
Prince
I almost started this discussion yesterday about the Native American civs. Not being mean, but they would be best be represented by stepped-up barbarians (excluding the Southwest tribes that built cities). It's not discounting that they existed, were people, and got royally screwed over by Manifest Destiny, it's just that, on a global scale, their biggest accomplishment was based on who conquered them.
BUT... they fill a nice hole on the map, they DO have some neat recorded cultural identities that make them fun to speculate on, and they've been included not only in Civ games, but in many period-appropriate RTS and strategy games for the entirety of video gaming.
Personally I liked when the barbarians were wild animals (Civ IV). Provided the same gameplay deterrent, but wasn't offensive to anybody. I think City States capture the feel you're talking about. Minor nations with less global influence, but still a lengthy history, artifacts and an impact.
I'm starting to think civ VII is going to have to radically change up the formula. Eurekas are a good move in the right direction, but the linear tech/civic trees make inclusion difficult for certain nations/cultures/civs. They seem to be aiming for diversity and inclusion these days, so it may be time for a rethink of some core mechanics. It's pretty common to see Industrial era civs with Ancient era powers at the moment. That isn't a commentary on that civilization, more the game's mechanisms and how specifically they tie themselves to European advancement.