NerfCothons
Warlord
I don't know, I haven't played the Mexican UHV yet. But I suppose it'll be hard without all farms and Cereal Industry + imported grain.
I agree that the Aztecs should collapse more often.
I think there are two ways the Aztecs live on. Either AI mismanagement of their conquerors (who often happen to be spawned by a civ with poor military technology) prevents a complete takeover, or the Aztecs become someone's vassals.
The tech level of the conquerors could be standardized when spawned by the AI. Guaranteed knights, bombards, and musketmen should improve the AI's chances.
You could also prevent all three native American civilizations from vassalizing to whoever triggers the conqueror event. If they are going to survive, the must do so independently.
Maybe we also build a plantation on the Cetchen Itza dye at the start of the 600 AD scenario so the AI will attack it? That city seems to sometimes stay independent for a very long time.