I disagree partially.
It boils down to whether you consider a power-up as something that comes immediately. I personally don't, for me a power-up is simply something that makes a person stronger. A power-up can be obtained throught training like Luffy's gears or in this case, Enma's taming. That doesn't make it cheap or easy. Every kind of new power needs some sort of mastery, I think. Once Zoro tamed Enma, he will be stronger than he is now and it will be because of his own determination. Since he is stronger than before, it is a power-up.
When you say:
I can agree with you even if I consider Enma as a power-up, since its power is only fully obtained once Zoro mastered Enma. I also like the comparison you made between Enma and battleing an opponent. Fights also seem to be a way in wich power-ups can be obtained (see Luffy's future sight).
It boils down to whether you consider a power-up as something that comes immediately. I personally don't, for me a power-up is simply something that makes a person stronger. A power-up can be obtained throught training like Luffy's gears or in this case, Enma's taming. That doesn't make it cheap or easy. Every kind of new power needs some sort of mastery, I think. Once Zoro tamed Enma, he will be stronger than he is now and it will be because of his own determination. Since he is stronger than before, it is a power-up.
When you say:
I can agree with you even if I consider Enma as a power-up, since its power is only fully obtained once Zoro mastered Enma. I also like the comparison you made between Enma and battleing an opponent. Fights also seem to be a way in wich power-ups can be obtained (see Luffy's future sight).