What I think is that if Aztecs were familiar with Iron working, all the same they could not occupy all the world. I doubt that they could occupy both Americas because once iron had been discovered there, the discovery would have needed only about century to get spread all over the continent. Both Americas of 15th, 16th centuries were not densely populated places, and it goes without staying that brave iron-clad Jaguar warriors were not enough to invade to cramped and heavily armed Europe full of soldiers and mercenaries of all kinds but they would be enough to prevent European invasion in early 16th century, when Europeans had only rudimentary artillery (bombards) and firearms (arquebusas) didn't play quite a great role in the battle. That time ould be enough for American Empires to preserve Status Quo with little territorial loses - such as Cuba, Carribean islands, Coastline from Venezuela to Argentina, maybe, Newfoundland, Bermudas. I think, if the Iroquis tribe of Manhattan had already been in the Union of a Long House, they would not have sold Manhattan to the Datch when the latter arrived in the region.
I am simply amazed with the picture of democratic Iroquis Republican Union rising in the end of 16th century and knowing Iron working.
