How would you predict that Aztec culture changed when the Spanish forbade human sacrifice?
I would predict two main impacts would occur.
First, the end of human sacrifices would have seriously detracted from the power and authority of the Aztec religious elite. This elite had been telling the people that human sacrifices were necessary to feed the sun and keep the Earth alive. When human sacrifices were done away with and there was no apparent damage to the sun or Earth, it would have decreased the prestige of the priestly class.
Second, the end of human sacrifice would have helped to tear traditional society apart and to give more power to the Spaniards. Removing a major aspect of traditional Aztec society would weaken their dedication to that society. As that society lost its hold, something would have to fill the void. The Spanish society and culture would have been the obvious candidate. As the old society and culture disintegrated, a new one would have to spring up in its place.