Fist of all, I love this mod. Able to fight back the Spanish invasion and ironically invade back, and conquer Europe. The funnest and what if game play ever. But, what I noticed they have fought back false deity (Spanish) and know what Europe is, yet lack of armor or some tech. I have one modding idea to upgrade Aztec armor. Once any European foreigner invades the Americas,( or once you land Europe and take over a city) be able to upgrade to better armor. For example, heavy infantry will wear the same colorful armor but with some plate on top. Jaguars/Eagle warriors upgradable to heavy chain still with the same armor but some mixed chain and all that show. I will love to mod this and share it, yet I lack TW modding knowledge.
TL;DR Able to upgrade Aztec troops with some steel armor mixed with original colorful armor.