I think problem is come from the misunderstanding of historical facts: Europens were never so stronger than Natives, and the fear of gunpowder is overrated.

Yes Spanish wear quality armor, and natives had only clubs, but natives are fierce troops and experienced warriors in scary jungles. Their army could devastate Spanish armies in a heartbeat. Natives also not afraid to death, and dont fear from the muskets. So M2TW is realistic about the Aztecs.

But in history, they were beaten by a bunch of Spanish bum. Why? Here is a small history lesson:

* Its long and tragic story, but simply: They thought Spanish are their gods. They opened their cities, and worshipped them. But ofcourse Spanish want no friendship but gold.
* They lost against Cortes because Spanish fooled them. So their King taken prisoner by Cortes and they slaughtered one by one.
* They do not fear the gunpowder. They fear that the guns are the work of God.

After terrible defeat of Incas, Aztecs ordered themselves against the Spanish. Spanish even lost battles against them, Cortes have been captured once..

But the problem is, unlike Mayans and Incas, Aztecs are not wise, cultured people. They were brutal and warlike. They never be popular on MezoAmerican tribes anyway. And many tribes choosed Spanish to fight together. . Spanish mostly won with help of the Natives.

And ofcourse, diseases came from european countries and did terrible damage on native's population. Europeans know that and they even sold their diseased blankets to native tribes.

All because of these; i can comment that with an alternative event, Aztecs could crush Spanish and M2TW's troop qualities are realistic. Only problem is, in M2TW you creating your alternative story, and putting the historical events in M2TW is much harder thing to do.