Well let's be honest here. If we are saying that Europe techs at a rate of one tech level every 11 years, then Mesoamerica is fantastically better than history would ever deem plausible. Between the dawn of the iron age and the plate mail of the 15th century is 1800 years. Getting to a "tech level" of 1437 (extrapolating backwards from 1448 gives the approximate date when Western Europe should have hit tech 2) by the arrival of Europe? Please. That is wildly generous.
Yes I know, they had very nice obsidian weapons and while they could not easily penetrate steel armor, they could kill. But look at the battles, heavy cavalry charges, gunpowder shock, and of course cannon more than decimated Mesoamerican forces. When the Mesoamericans were successful (e.g. the early Chichimeca War) it wasn't because they were remotely close to on par with Europeans, it was because they were not engaged in direct warfare and had huge numbers.
But what about non-land techs? Well, given that production income represents the ability to extract resources from the land, there are many basic things you cannot do. Without draft animals, you are limited to human power - getting European scale crop returns is impossible. You don't have iron for mining or for lumbering. Trade and government ... well again that doesn't work out so well. You need paper to make efficient commerce possible. You need math skills that the Aztec never developed (their math was good at solving many problems but they lacked a lot of basic arithmetic like reciprocals and some area calculations that could have more efficiently solved known Aztec math problems). With land tech you could at least make some vague hand waiving about better bows and more balanced tepoztopilli, but for the others, there just isn't a way for the Aztec to get as much out of things with all the back technology of Europe. There is a reason why the Spaniards elected to "bribe" the Mesoamericans by teaching them European agriculture and technology in order to pacify them and a reason why the natives took the deal.
Yeah, it is going to be boring to play Mesoamerica in EU, but if we are saying a unified tech tree and the numbers are roughly linear, then the Mesoamericans should have just about nothing until the Europeans arrive. We are talking about jumping a larger technological gap to 1500 than from 1500 to today.
Frankly, the only way I see Mesoamerica nations surviving is if they can arrange friendly relations with the Europeans and use irregular warfare in a bid to get concessions for a lower cost than conquest. This is where you could make Mesoamerica interesting. Give the area special abilities like declaring a guerrilla war - your troops cannot siege or hold territory, but can inflict losses on Europeans and then retreat at no loss of war score. Or let them offer gold to Europeans in exchange for technology (like swords and horses) up until they have half the European tech level. Make it so you lose these advantages as soon as you westernize and have pressures on playing too nice with the Europeans (e.g. European powers press you to convert to Christianity, doing so reduces your special options and makes the people very unhappy).
At the end of the day, I would be highly disappointed if any Mesoamerican state wasn't hard even for strong players to survive and thrive, particularly without flagrantly abusing game mechanics.
