Rather than argue, I shall include my list of 19 civilisations and explanations for why.
1. SAXONS/HUNS I am poking fun at the Germans, and at the same time trying to combine the German-Austrian group into a single civilisation. They were a massive influence in history, destroying Rome, bringing about the age of Swordsmen, spreading Saxon culture, &c.
2. BRITONS by which I mean the Brittonic Celts who inhabited the British Isles in ancient times. DNA tests show that Britons were never displaced: they assimilated foreign cultures. Whether they like it or not, the Scots and English share common ancestory and created the British Empire by working together.
3. ROMANS who spread their empire as far north as Brittannia, as far west as Spain, and as far south as North Africa.
4. JAPANESE as they are unique and dangerous. They built the first Ironclad, and held empires more than once.
5. FRENCH who were the primary challenger to a British Empire. Ironically, the French are also of Brittonic decent but to combine French & Britons would be INSTANT CONQUEST VICTORY!
6. SPANISH with the first sea-faring global empire, destroyers of the Inca. Spanish are unique because they can actually smell gold a thousand miles away!
7. HAUDENOSAUNEE (Peace Mongers) who held a large land-mass in North America and allied with the Britons time and again. Even sent food to help during the Great Potatoe Famine.
8. INDIANS who built the great Taj Mahal, and controlled the massive empires of varying sizes. Current day India is actually one of the smallest Indian Empires.
9. PERSIANS who held a massive and unique empire, lost to the Macedonians of eastern-Europe but the language survives. Persian is a lovely language, and they made-up the idea of a Geenie.
10. MACADONIANS/GREEKS because they have Alexander the Great and left the most artistic and detailed statues ever crafted.
11. EGYPTIANS who had a very unique culture, built massive monuments from sandstone and held a large empire.
12. RUSSIANS who were influenced by Viking and Mongol migrants! Held one of the biggest and least well known empires, still hold vast political influence. Most powerful member of the former Soviet Block, and current centre-piece of the vast Russian Commonwealth.
13. MONGOLS which Ghengis Khan led to victory all over the place. Still exists as a poor land-locked nation between Siberia and China.
14. CHINESE because they built the Great Wall of China to hold the Mongols at bay.
15. INCA who suffered terribly at the hands of their own culture and later at the hands of Spanish Conquistadors. Left some funky ruins which people love to visit.
16. VIKINGS because they caused havok and held an empire spanning across Scandinavia and British Isles. They also controlled a rare example of European slave trade.
17. FLEMMISH/DUTCH homeland to William of Orange, and held an enormous sea-faring empire which included Australia and South Africa. Ultimately these places were swallowed into to the British Empire, as was William himself
18. ETHIOPIANS who held a medieval christian empire, and because currently there is too little to represent the many African civilisations and this would help ballance that.
19. AMERICANS, because they sponsor game development.
Ommited: English, because American game-designers don't know what English means! The English Empire was medieval and held chunks of Europe. The English were Celts who had adopted a Saxon culture. English constitute
part of the later British civilisation.