Guy
The “natural nobility” idea may be true, if we accept that Adam’s line got big ideas in the garden. I don’t think it’s absolutely necessary in order to confirm your dispersion idea. The whole history of humanity - including the formation of Israel - involves the mixing of people groups by conquest, infiltration and assimilation.
So for both exegetical and anthropological reasons, we don’t need to say that the Table of Nations represents the spread of mankind on a virgin earth, but only those nations which could be seen as descended from Adam as a mixed population at the time of writing.
That happens to correspond pretty well with the distribution of the western neolithic (anatolian) dispersal, and so it’s not unrealistic to match the account with that.
That fits very well with the Genelogical Adam idea, I agree.