When choosing civilizations, CIV4 developers should consider civilizations that had/have impact on the developmet of the world in various aspects such as culture, religion, military, commerce etc. The civs we have so far in CIV3 and addons have been picked well, and all of them left some trace on this world. The guy who insists on Serbs and Albanians or whatever slavic or non-slavic tribe inhabiting the Balkan must know that those little nations cannot be considered as particular civilizations, because they are only fragments of overall Slav population in Europe, which in this game is well represented by the Russian civilization; apart of murdering the Austrian prince, and mass murders in Balkan wars throughout 20th century, Serbs haven't made anything that would qualify them as a civilization - they are only a part of wider Slavic Orthodox Christian civilization. Similar applies to Albanians, except that they could be categorized (mainly) as part of Ottoman Islamic Civilization.
Here is my proposal for the civs, and there should not be too many:
Europe:
England (Anglo-Saxons), Germany (Germany and Austria), Russia (Slavs), France (Franks), Italy (Rome), Hispania (Spain, Portugal), Scandinavia (Norway, Sweden, Danemark, Finland {terve

}), Ottomans (Turkey and turcophonic countries in the Caucassus), Greece and Netherlands. (11)
Asia:
China, Japan, Arabia, Hebrew, India (India, Bangladesh,Pakistan), Indochina (SE Asian countries and cultures), perhaps Korea (although I don't know much about their culture and achievements), Babylon and Persia (8 or 9)
Africa
Egypt, Carthagene, Zulu, Abyssinia (Ethiopia) and Subsaharan Africans (somebody listed names of all those small nations and cultures in that region) (5)
Americas:
Maya, Inca, Aztec, Sioux, Iroquois, North Americans (US and Canada) (6)
Australia/Oceania:
Poor guys didn't even had chance against the White Men, but frankly they haven't left much behind them except the big heads on Easter Island.
As for small nations and native tribes world wide, their names should not be left out. Perhaps it would be good idea to have them not only as barbarians in those small sheds but also that they have their own cities (one or two) without possibility to expand (that they cannot produce settlers) or develop technology. In fact, that is main reason why they haven't made it to become big nations.
PS. My intention was not to offend anyone when I said "small nations".