I think the current devs intend to make this game historical period forward to the 19th century, so here’s my suggestion for Asian civs.
But I won’t mention much about India because British raj a sensitive topic.
1.Japanese can start from Bakumatsu (1853), or from Meiji era(1868).
If choose the former, current models can continue to be used, and don’t need to change the design.
If choose the latter, the models of Japanese buildings and military units should be replaced with European styles, to reflect the influence of western culture on Meiji era.
2.Replace monks with bureaucrats because Asian civs have long tradition of bureaucracy.
Sohei Archer → Bugyo(奉行) if Bakumatsu, or Kaitakushi(開拓使) if Meiji
Shaolin Master → Qinchai(钦差)
3.Change consulate allies options.
Japanese consulate should remove all the options, include the Japanese Isolation, and replace it with British, Germans, Russians, and United States(provides the same building wagons as Dutch, but different armies).
Yes, this new list is too repetitive with the Chinese consulate allies, so one solution is to limit the number of times a player can choose a consulate allies in each game.
4.Replace wonders with signs of modernization, but acceptable to change only the model without change bonuses.
For example, Summer palace can be replaced by Kaiping diaolou, which is a kind of private fortress in southern China from 19th century, with the introduction of western architectural design, and is on the World Heritage List.
Another example, Great buddha can be replaced by Rokumeikan, which was a foreign pavilion in the Meiji era, used to entertain diplomatic envoys, so it is very suitable for providing the bonuses of see all enemies’ LOS, same as Great Buddha.
5.Add more fake rev cards, because Asian civs are not feasible to make rev options available as European.
Fake rev cards mean cards like Tupac Rebellion in Inca, and Belgian Revolution in Dutch.
For example, Chinese already have Boxer Rebellion card, so just need to add an effect that converts villagers to boxers, a Javanese Spearmen-like unit.
Satsuma Rebellion can be a historical material for Japanese fake rev cards.