Yes, I definitely agree that Asia, South America, and Africa should have more minor native civs. However, since I’m not that familiar with the history and cultures of South America and Africa, I’ll focus on Asia. Here’s a map that I made based on JadenJames03’s map about the plausible new maps that we could add (sorry for my bad handwriting).
For those who cannot see my handwriting clearly, here’re the additional maps (will present them following the order from north to south and from east to west):
Yakutia, Yenisei, Baikal, Eurasian Steppe, Ryukyu, Formosa, Jiangnan, Huguang, Bashu, Lingnan, Yungui, Micronesia, Filipinas, Siam, and Andaman.
As for the natives of each map/region, here’re my suggestions:
Kamchatka: Koryaks, with a possible unit being the Koryak Bowman, a bowman with a short range though a lot of pierce and melee armor, as they had the tradition to wear heavy lamellar armors.
Yakutia: Yakuts, Evenks
Yenisei: Nganasans, Kets
Baikal: Buryats, Mongols
Eurasian Steppe: Kazakhs, Dzungars. A possible unit for the Dzungars would be the Camel Gun, a light cannon installed on the back of a camel.
Mongolia: Mongols, Dzungars. Mongols should be a minor civ in their homeland, and a possible unit would be the Mangudai.
Manchuria: Of course the Manchus, and there’s already a unit named Manchu in the game, suitable as their unique unit. A possible secondary unique unit would be the Manchu Heavy Cavalry, which is a heavy melee cavalry clad in lamellar armors and is good against infantry. Alternatively, they could have the Dunche or Shield Cart, basically a cart or wheelbarrow pushed by manpower and mounted with wooden planks on its front and sides, and the soldiers inside could shoot out with their muskets or arquebus. Should be a unit with a lot of pierce armor.
Hokkaido: the Ainu should be a minor civ on this map, and a possible unit would be Ainu Bowman or Ainu Horse Archer.
Korea: the Koreans should be a minor civ here. A possible unit would be the Joseon Musketeer, a cheaper and weaker version of Musketeers.
Central Plains, Yellow River, Jiangnan, and all other maps within the territory of China Proper: a non-religious minor civ would be the Weisuo, basically militia garrisons established by the Ming Dynasty. The soldiers inside a Weisuo were farmers most of the times, but were also trained to use basic weapons to a certain extent. In case of war they would be recruited en masse. A possible unit would be Chinese Hand Cannoneer, a cheap, weak, short-ranged infantry that fires in quick successions, similar to a Chu Ko Nu.
Central Plains, Yellow River, Silk Road: another non-religious minor civ, but this time specifically for these three maps, would be Northwest Rebels. A possible unit would be Mianjia Jun, a melee cavalry wearing layered cotton armors thus having high pierce armor, good against ranged infantry.
Central Plains, Jiangnan, Lingnan, Korea, Honshu, and Ryukyu: Wokou, it should be a minor civ on these maps. Possible units include Wokou Ronin, Wokou Monk, etc.
Lingnan, Yungui, Indo China: a possible minor civ to add in these regions would be Yao/Zhuang, and a possible unit for them would be Lang Bing or Wolf Troop. It’s a shock infantry armed with a V-shaped shield and a sword or a short spear. Alternatively, they could have the Poison Crossbowman, which deals a similar effect as the Jungle Bowman of the Inca civ.
Bashu, Huguang, Parallel Rivers, Yungui, Indo China: Miao/Hmong as a minor civ, and a possible unit would be Tu Bing, a heavily-armored javelin thrower.
Huguang: Wutang as a minor civ, and a possible unit would be the Wutang Monk, which can heal friendly units and deals bonus damage to treasure guardians and enemy explorers.
Formosa: Formosan Natives, possible unit Seediq Warrior
Ryukyu: Ryukyuan, possible unit Ryukyu Samurai, similar to the Japanese one but slightly faster and is armed with a shield (due to Chinese influences handheld shield was more prevalent among the Ryukyuan army than among the Japanese). An alternative or secondary unit would be the Ryukyu Hand Cannoneer, due to close ties with Ming China the Ryukyuans would import hand cannons from China.
Filipinas: possibilities are many, including Aeta, Visayans, Ilocano, Moros, etc. Maybe a unit wielding the Kali sticks?
Borneo: Dayak people, a possible unit would be the Dayak Headhunter.
Malaysia: possibilities are many, Jehai, Batak, Orang Asli, etc. A possible unit would be the Jehai Blowgunner.
Indonesia: Javanese, Acehnese, Moluccans, etc. Could have a naval unit.
Siam: Siamese/Tai peoples, an elephant unit for them most likely, alternatively they could also have a unit wielding twin swords, such a technique is called Daab Song Mue in Thai martial arts.
Andaman: Andamanese, a possible unit would be the Andamanese Bowman, fast and high attack, though has a rather low HP, best used for hit-n-run tactics.