I can see most extraterrestrial colonies having small settlements but why aren't planets more mixed? Shouldn't betazed be about 50% betazoids, and the other 50% be randomly mixed up of all other Federation planets? Shoudn't tons of aliens have expatriated to Vulcan, or Bolias?
Shouldn't, by this point in the 24th century, planet of residence have less correlation with your species?
And shouldn't like 20% of the population be noid-mutts?