So, I just used the debug mode to observe world history as Babylon in hiding in Antarctica, from 3000 BC to 1867, and I'm impressed with how well this mod is coming along. Without player interaction, I notice, the game plays out very much like history

. Well, unless you count Sweden becoming a superpower, conquering all three pre-Columbian civs, and a Muslim Danelaw. But I digress.
I do still have a couple things I observed that I feel I should comment on, though. Or... more than a couple. As a disclaimer, I have no bloody idea what I'm talking about, so don't take any of these suggestions too seriously.
Europe
* Ireland is already (sorta) represented by the Celtic city at Dubh Linn, even if they just exist there to be conquered by the English or Vikings. But I think the Scots should be represented the same way as well, and Scotland itself should be removed from England's flip area. A few longbowmen in Edinburgh or Inverness or whichever should at least give England some work to do on the Isles before the age of colonization begins; as it is, it's just sort of a walkover for England.
* There really aren't very many big European wars, in my experience, at least before the modern era when they really just become world wars. The only time I really see them is right after the Reformation, and half the time (as was the case in this game) there's no Reformation wars at all. Maybe colonial wars could serve the purpose of pitting the Euros against each other more often.
Latin America I think I heard that Leo plans to focus on Latin America soon, which is fantastic. So most of these may have little bearing in the future. I feel like I should list them any way.
* Pre-Columbian Mexico really needs a better city name map. I'm kinda tired of seeing Teotihuacans, Tuitans, and what not all over the place. I'm sure there's resources out there with the names of some pre-Columbian settlements at or near the spots being settled (except for those in Texas or whatever, silly Aztecs).
* When Aztec and Inca respawn as Mexico and Peru, they should receive a larger tech boost to keep them from being more or less immediately re-subjugated (in my case by France).
* For some reason the respawned Incas would not be renamed 'Peru' after their respawn, even though their cultural adjective was 'Peruvian'.
* I think the barbs in the Andes need to be toned down slightly once the Inca Empire reaches its full extent. They tend to get raze-happy, which leaves swathes of city ruins in the Andes which the AI generally refuses to re-settle.
* There should probably be one or two independent cities in the Andes for the Inca to conquer. In real life, the Incas expanded their empire by military force, conquering older empires like the Chimu and subsuming their territory. (The same could be said for the Aztecs, but really, most of their important enemies fall under the same tile as Tenochtitlan-Mexico, so it's sorta futile). Currently, with the exception of Tucume, the Inca expand simply by settling territory, which is sort of anti-climactic.
* To my knowledge, I've never seen the Maya respawn. I think that they should have a good chance to respawn in the 19th Century and cause trouble for Mexico, as this is the period in which the
Yucatan tried to gain independence from Mexico.
* A good solution to America's refusal to expand to the Pacific may be to have Mexico gain cities in California and the southwest, and then encourage the United States to go to war against Mexico once or twice to take them.
* Mexican and Andean cities currently don't rename to post-colonial names following respawns, unless they happen to have been conquered by Spain, which is increasingly often not the case.
* The Arab-speaking nations (Arabia, Moors, and Egypt) should have more names for Mexican and Andean cities when they get the conquistadors event. In particular, El- or Al-Meksik for Tenochtitlan-Mexico and Wadi al-Hajara for Guadalajara come to mind.
Africa
* When controlled by Rome, at least, Egypt should flip to the Eastern Roman Empire along with Anatolia, the Balkans, and the Levant.
* I think the barbs in the Sahara should be reduced a bit earlier than they are, as it's a bit odd to see camel archers still razing Egyptian cities in the 1600s.
* There should be a couple more African independents or minors, like Kanem-Bornu and the Zulu, so that there isn't so much empty space in the African interior.
* The Malinese have had it too good for too long!

Mali has been known to occasionally win historical victories by accumulating extreme amounts of gold, and usually sees no action in game except against barbs. Maybe there should be a couple other West African states, like Songhai, Ashanti, Sokoto or whatever to pose at least a small challenge.
Trade Companies
As it is, I think it's a bit deterministic that England's only potential Trading Company event is to conquer India, or that Spain's is to capture the Philippines. Perhaps all the options should be open to all the colonizing countries (albeit, that the AI should be heavily inclined to stick with its historical choices) so as to make the Trading Company race slightly more competitive.
Other
* It's nice that Hawaii is actually a nice place to settle now, but no one actually seems to pay it any mind. Maybe there should be an independent/minor Kingdom of Hawaii on the island that potential imperial powers could conquer.
* I think there may need to be some slight tech nerfs. By 1840, England was researching fission; and Portugal was researching combustion, and was in the lead in score despite having very few cities.
* Maybe violent revolutions, like civil wars, the French Revolution, the revolutions of 1848, or other similar events can be represented in game.
... That's my two cents.
