The more I read about him the more I think a strong willed emperor would have put much more of a fight. He just didn't decisively and at least once was just so afraid of death that let himself be kidnapped rather than put a stop to the spaniards.
I've heard that he was so religious he didn't want to fight the spaniards in fear of them being Qutzalcoatl But that's heavily disputed, to the point I find no merits to the idea. So, why? why let the spaniards into your inner circle? why let them kill your subjects in Cholula and do nothing? why keep showering them with gold? why let them kidnap you? just seems (to my untrained modern eye) incompetence all over the place.
It is not until Cuitlahuac that the Mexica finally showed strength. Ultimately smallpox would have wiped them all anyway but at least he put up a fight.
u/400-rabbits goes into a lot of depth on Moctecazuma and the misconceptions surrounding him in http://askhistorians.libsyn.com/askhistorians-podcast-episode-005 this podcast.
Moctezuma was not incometent, at least not in the traditional sense. Emperors were actually elected by a panel of Nobles, and was chosen specifically for his military record and leadership skills. That said we have to understand a very important thing. The Aztecs were not a warrior society, they did not have a professional standing army. Because of weather patterns and agricultural cycles Warfare season only ran for a couple of months a year. May through September was the rainy season. Making roads muddy, and rivers too swollen to cross. Also the need for supplies has to be factored in, so war was only waged after the harvest and during the dry season, putting it between early December and early April. Cortes entered Tenochtitlan on November 9, putting it towards the end of the harvest. Most of the people who made up the army were still busy with the harvest. Some believe Moctezuma was planning on raising the army quietly and kill the Spaniards as they were trapped inside the city. He may have also wanted to keep an eye on them while the army readied itself. The knights were available for fighting since they didn't have to work the fields, but Cortes had been riding an undefeated streak through Tlaxcalan territory. If Moctezuma sent troops to meet the Spaniards in battle, they may be badly defeated, and he would loose credit and may be ousted as Emperor. So allowing them to come in and get everything ready seems to be the right thing to do. Unfortunately for him, Cortes was extremely paranoid and decided to take him hostage. Cuitlahuac was then elected emperor, but there was no Aztec uprising until Cortes left for the coast to face a force sent to arrest him, and Alvarado was left in charge and ended up massacring thousands of Festival participants at the temple of Toxcatl. We do have an example that trapping them in the city worked. During the Battle of La Noche Triste (Night of Sorrows) Cortes' casualties were about 860 Spanish soldiers, and over 1,000 Tlaxcalans killed. It is widely believed that Moctezuma knew Cortes was not the God Quetzalcoatl. He had received reports of ships off the coast, and from trading posts in Maya territory he had heard stories of strange men washing up on the beaches. One chest washed on what is now Veracruz and was taken to him. It had some clothing, a few precious stones, and a sword. Also, Cortes himself introduced himself to Montezuma as an emissary of another powerful king. A good read is "Mexico and the Spanish Conquest: Second Edition" by Ross Hassig. It's not a terribly big book, and pretty easy to read. Another would be "The Broken Spears: The Aztec Account of the Conquest of Mexico." Edited by Miguel León portilla The story that has been popularized was more than likely a propaganda campaign to portray the Aztecs as superstitious and ignorant. Therefore justifying the conquest, they "needed" to be civilized and educated.
A good read is Mexico and the Spanish Conquest: Second Edition" by Ross Hassig, and "The Broken Spears: The Aztec Account of the Conquest of Mexico" edited by Miguel León Portilla.