So what do you think guys? Interesting? Yes or no?
I think this is a great idea. I agree with every one of your points.
5) (rarest) if they have NO contact with other races when a particular age ends or begins. Unnamed civs that have not had any contact with any of the above (something nearly impossible) will begin forming their own proper civilizations.
It's not impossible though if they live on an island or they live underground. Think of uncovering vast, underground bat man temples and villages as you dig deep.
3) One of their camps is actually taken over by the new racial mechanics, then they rebel and break away. They take on the trappings of the group that conquered them sociologically and technologically, assuming they actually break away in rebellion, or are not exterminated first.
Perhaps there could be conflict and unrest within the civilisation between those who would prefer to return to the old ways rather than adopting the ways of the conquerer and those who seek modernisation. That could be the case for all your points though.
Basically, my idea is predicated upon making this stuff function for the purposes of the new conquest mechanics, where one civ can take over a location just by occupying the central place of it.
I hope Toady introduces a mechanic like this for taking over a dorf fort. Would add an entire new dynamic to the game if you had to say, defend your Wagon (early embark), your Trade Post (mid embark) or Highest ranking noble's throne room (mid-late game).
Anyway, the point is that these unnamed civilizations are starting off from a point of disadvantage, but they can grow larger very quickly once they reach the right age.
It'll be especially interesting once Toady implements digging for NPCs so they can carve their own areas out of the underworld.
Anyway, I really like the idea of underground civilizations growing over time.