People far more articulate than I have answered all of those points. You don't like the word "primitive" because your liberal background forbids you from objectively judging cultures and civilisations. Now there's nothing wrong with that but political correctness is not endemic.
I've outlined above why I judged the aztecs as primative. The fact that they had a small amount of bronze is hardly relevant when Europe had been making arms and armour out of bronze for millenia - the Mesoamericans clearly did not, this makes them objectively inferior to European heavy infantry from hoplites through to legionarries through to the knights of the EU 3 era.
This is a suit of Gothic Plate Armour, produced around the fifteenth century:
This will stop literally anything that the aztecs could throw it it. It is a serious piece of equipment.
The aztecs by contrast were rolling around in this:
Which clearly, is going to do bugger all against a broadsword or a pole axe, or an arrow from a crossbow or longbow.
Again when it comes to weapons, the Aztecs are woefully behind the rest of the world. Almost entirely wooden, or wooden with obsidian shards, they would have simply shattered against chain mail, in fact obsidian would wear out very quickly even cutting through flesh, when metal weapons simply wouldn't.
Their ranged weapons don't seem to be more advanced than in antiquarian times - hunting bows and slings/darts, certainly nothing like the longbow, let alone a crossbow (which was a far, far more advanced piece of tech).
So in warfare alone, we can see that the Aztecs were *way* behind Europe. It seems to me that had one of the MesoAmerican cultures had developed the capacity to produce a large amount of bronze weapons would have quickly dominated the surrounding states - who would in turn have adapted themselves. Such an event never happened, so either the Native Americans don't bother competing with each other for land and resources, or they lacked the capacity to do so. And this is something that happened elsewhere 2000 years prior. Yet in EU they start off more or less the same level as the rest of the world, which is rather generous.
tldr; Aztecs had primative warfare. Can't be arsed going over any other areas, other people have already done it better.