I really like the concept here. You are one of the few people in this forum who actually understand the issue about the 'names". In the case of the Purépechas of northern Mexico, the title of
Tarascos/Tarascans is considered very offensive. I can't believe how CA didn't paid attention to this; it's almost like they just searched it up on Google and used the first name they've found.
About the
Chichimecah, the main issue is that this title is not concise. Many historians believe that it was the Mexica and other peoples who called them that way because of their pratices and culture. The word
Chichimecatl (singular) has a variety of possible meanings, but the most accepted are
"Inhabitant of Chichiman" (
The Land of the Milk) and "
One Who drinks Milk". For uncertain reasons, this term was often used to describe nomadic, hunter-gatherer people considered "uncivilized" or "barbarian". The point is that there were many ethnic groups called Chichimecah, and the
Otomitl/Otomí and
Zacatecatl/Zacatecos, who lived in central Mexico, were the main ones. Here's a map regarding the most prominent Chichimeca groups inhabiting the valley at that time (although it's from 1550, the situation was basically the same in Pre-Conquest periods):
So, my idea is that instead of a single playable faction, you could make the regions of Zacatecatl and Otomitl as heavily garrisoned "rebel" villages/towns with the title of
Altepetl (which means city-state, town, village, etc) followed by the name of the local communities. For example, the hypothetical hometown of the Zacatecos could be called
Altepetl Zacatlan.
Armies of these ethnic groups should be recruitable at the entire region of Central Mexico (including at territories of the Mexica, Tlaxcalans and even Spanish), as
Area of Recruitment units and mercenaries. Historically, the main advantage of the Chichimecas, Purépechas and Tlaxcalans over the Mexica were their expert use of the bow. It's registered that the army of Mexica emperor Axayacatl was completely destroyed only by a number of archers hired by the Purépecha Empire, who kept firing on their enemies from the walls of their capital, finishing the battle with a ferocious charge. Judging by that, it shouldn't be easy to conquer these "rebel" Chichimeca settlements, since the garrison armies would be filled with skilled archers who were also formidable hand-to-hand combatants (a real unique trait). The same logic would be applied to the Purepechas and the Tlaxcalans.
Also, it would be interesting to point out that important cities in the New World (Mexico and the Andes, for the most part) had flags or emblems representing the local aristocracy, their families or even the symbolism/etimology of the city itself. The
Lordship of Tlaxcala/Tlahtoloyan Tlaxcallan (this is how Tlaxcala as a faction should be called in-game - there wasn't a City-State named Tlaxcala, it was a province), a "confederation" formed by the lords of
Ocotelolco,
Quiahuiztlan,
Tepeticpac and
Tizatlan, had four distinct flags representing each city/lord. The Triple Alliance, composed by
Tenochtitlan,
Texcoco and
Tlacopan, also followed the same system.
Mods like
Stainless Steel have a script that automatically gives the title of "Duke" (a trait/retinue which offer unique advantages) to family members governing a certain settlement. Something like that would fit the political organization of the New World in a very convincing manner. I have most of the desings of these emblems stored in my computer as a resource for old projects.