I largely agree with Seancolorado, i like your spread! (i even liked your format so much i stole it!)
I would make a few changes though... Here's my justification:
North and South America account for 29% of the worlds land mass (about a 16.5:12.5 split).
Asia accounts for another 30%
Europe (to the urals and caucasus) accounts for about 7%
Africa accounts for another 20%
Oceania (Australia and the pacific islands) accounts for another 5%
Antartica accounts for around 9% - this portion is written off for obvious reasons
That leaves a good 91% of the earths land mass inhabited by civilizations. For a good fair game, i'd want a good fair spread where everyone has around the same competition and area to expand.
So with 22 civs, that means roughly 1 civ for every 4% of earths land mass. That will account for 88% of the land mass, and the extra awkward 3% can just be cut from asia and north america because of the crazy tundra. So for a good map spread here are my choices:
Americas, 6 civs:
1. Iroquois: Starting around the Eastern Great Lakes
2. Aztecs: Starting in Northern Mexico (historically the Nahua people migrated south from northern mexico to found th aztec empire)
3. [Speculated North American civ]: Starting in a midwestern/western location, depending on the civ. Probably positioned slightly more north than historically located.
4. Maya: Starting in southern Guatemala/Honduras for expansion into South America
5. Brazil: Positioned in very southern Brazil, around Sao Paulo/rio
6. Inca: Positioned in western mid Peru
Europe, 2 civs:
7. France/Germany: I'd prefer France to give a bit more space between this civ and Russia/Ottomans
8. Russia: Starting in Moscow region, also allows for Asian expansion
Africa 5 civs:
9. Morocco/Carthage: Either would do allowing for African and European expansion
10. Egypt: potential for asian, european and african expansion, not trapped in a peninsula like arabia
11. Ethiopia: filling out the east
12. Songhai: filling out the west
13. Zulu: filling out the south
Asia and Oceania, 9 civs:
14: Ottomans/Byzantium: i would prefer the ottomans, but the fit the same spot
15: Babylon/Assyria: I would prefer Babylon starting in Iraq for some more distance from the ottomans/byzantium
16: Persia: starting north of modern day iran, close to the caspian sea for a more competitive central asia and easing the pressure on the middle east.
17. Mongolia: starting in central mongolia to fill out the plains
18. China: starting in north east china
19. India: starting in north/north west india
20. Siam: Starting in northern thailand/myanmar
21. Indonesia: Starting on java for distance from siam
22. Polynesia: starting probably in New zealand allowing for some more expansion opportunities and greater competition for indonesia
Civs not listed at all:
America - Trying to avoid the european american civs (bitten the bullet for brazil) and occupies a similar location to the Iroquois
Arabia: caught in a peninsula in a cluttered area
England - island civs generally have difficultly expanding, particularly near continental civs who can much easier, also limited space in europe
Celts - Same as above
Spain - Too close to Morocco, not enough space in europe
Portugal - Same as Spain
Germany - Too close to france, europe problem
Sweden - Icy area not often settled by the human player
Denmark - Same as above
Huns - No need for them
Austria - too close to germany
[Venice] - cluttered europe
Rome - "
Netherlands - "
Poland - "
Greece - too close to ottomans
Korea - Could have been China or Korea, but China is too important to leave out
Japan - They start on a relatively small 'island'. Unlike Indonesia and Polynesia, no UA incentive to justify