Of course, another major factor there is that just about everyone subject to the Aztecs hated them for a variety of reasons, but most obviously all the raiding/

Of course, another major factor there is that just about everyone subject to the Aztecs hated them for a variety of reasons, but most obviously all the raiding/kidnapping and blood sacrifice. That's not to say the Spanish Empire was necessarily better, but their opportunities would have been much slimmer if the Aztecs had been even a little bit less all-around cruel.