Currently, the Indians are the strongest civilization in Dynasties of India, simply because the Indian civilization has actually been removed! If you consider the Indians as a civilization in Dynasties of India, they’d have all the bonuses combined of all the Indian civilizations, and steamroll any other civilization.
Correspondingly, it might make sense to do the same thing to the Chinese, as a way to address political issues. We cannot have the Tibetans as a faction in AOE, simply because you could now have the Tibetans fighting the Chinese, and the Chinese censors would nix sales in China proper. Same goes for the Uighurs, both ethnicities, if I recall, having sacked the Tang Dynasty capital in the past.
Consequently, the Dynasties of India approach might actually be appropriate as a way to remove the Chinese faction from the game, and possibly introduce traditional enemies of China into AOE2 without offending Chinese censors. It would also present a fairer and more interesting depiction of the Chinese, who are often shoehorned into mid-late game fast tech strats.
Since splitting China into different regional civilizations would affront Chinese censors, the obvious way to do this would be to divide the Chinese civilization into different dynasties, namely the Tang, Song, and Ming of AOE4, with the current Chinese civilization being reworked into the Ming civilization. To complete the trifecta, it would also be meaningful to add the Jurchens in, who eventually toppled the Ming and established the Qing Dynasty.
The Chu Ko Nu would also be repurposed as a regional unit, as opposed to a unique unit, since the Chu Ko Nu is both ancient and relatively useless (a civilian home defense weapon).
The rough outline of the Tang / Song / Ming / Jurchen civs I’d have in mind would be:
Tang Dynasty, cavalry and infantry-oriented civilization with military bonuses with early power peak.
Unique Units: Jian Swordsman, an infantry unit with bonuses against other infantry, but not fast like the Jaguar Warrior.
Reductions to cavalry production costs, cavalry production time.
Song Dynasty, economically-oriented archer civilization peaking before the current Chinese civilization.
Unique Units:
Shen Pi Nu, a crossbowman that ignores pierce armor, but has a relatively high reload time.
River Junk, a transport ship that allows units inside to fire out.
Reductions to villager production time, reductions to villager cost. AOE1 Shang redux. Alternately, let them build a second town center in Feudal Age; i.e, they’re turtle Cumans with walls.
Ming Dynasty, economically-oriented archer civilization, basically, the current Chinese civilization.
Unique Units:
Changdao Arquebusier, a halberdier that can change into a hand cannoneer.
War Cart, a siege weapon that allows archers inside to fire out, possibly with a melee attack against cavalry.
Jurchens, militarily-oriented cavalry and artillery civilization, that only comes into its own during the Imperial Age. Intended to counter the Ming Dynasty.
Unique Units:
Manchurian Knight, a slightly slower knight that can transform into a cavalry archer with bonuses against infantry. Intended to depict the Manchu mastery of anti-infantry horse archery, as well as their heavy cavalry.
Shenwei Cannon, a horse-mobile bombard cannon that is intended to be strong against infantry and archers. Has to deploy in order to fire, like a Trebuchet.
Basically, having multiple Chinese civs help deal with complaints about the monochromatic nature of China in AOE games, by allowing different strategies to be viable; i.e, early-game aggression with the Tang, economic play with emphasis on navy with the Song Dynasty, old-style Chinese fast tech with the Ming, and late-game dominance with the Jurchens, if they can ever survive to that point.
Moreover, this also opens up opportunities for introducing other civilizations related to China, such as the Tibetans or Uighurs, but also enables the addition of more obscure (and subsumed civilizations) such as the Bai people (Dali civilization).
Tibetans I already have in mind; i.e, a cavalry-based civilization that has strong healing ability, or a very strong raiding civilization that falls apart in pitched battle.
Uighurs and Bai are more of a mystery.