The main benefit of eagle warriors, besides their increased resistance to conversion, is their speed. Eagle warriors are fast - very fast. Use them as you would scout cavalry. They are invaluable for revealing terrain features early in the game. Later on, use them to scout ahead of, and to the side of, your main army, especially when moving through unfamiliar terrain.
Aztec villagers have the ability to carry five additional resource points.
This may not seem like a big deal, considering that they harvest resources at the same rate as everyone else, but in fact, carrying extra resources gives the Aztecs a tremendous advantage. It lets villagers spend less time in transit per resource point, thus getting more resource points into stockpile sooner. Faster accumulation of resources lets the Aztecs advance to the dark and feudal ages sooner than their opponents and opens a wide range of other strategic possibilities. At first glance, the fact that Aztec military units are produced 15 percent faster than other civilizations seems to be a significant advantage. When you look closely at the way real people actually play the game, you discover that the rate at which units are produced is not as important as the actual number that are produced.