Because I am talking about cultural similarity. England and America have completely, totally differant and seperate cultures. Don't get me wrong; I am definately aware that the Portugese and Spanish are two differant nations, and I respect them for that. I am a great proponent of national individualism! (1) However, Spain and Portugal, just as Austria and Germany, have very similar cultures.
I believe, based on the entire Civilization series, that what civs are included should be based on (a) cultural uniqueness, and (b) relevance.
Now, slightly off-topic...
In response to the many suggestions of expanding African civilizations, or "why add more European civs":
For the latter reason is why I don't think more African civs are needed. African nations such as the Zulu, the Nubians, and the (2) Northern African Moors were really the only civilizations from that region that played a major role in world or regional affairs. In addition, they were all culturally quite unique. Regardless of questions of European imperialism and racism and whatnot, it is a fact that African civilizations had less of an impact on the world than European or Asian civilizations. This is only exacerbated by the fact that up until recently (and even recently), Africa was less nation-based that tribe-based.
