Naruto may become more cautious. With a prosthetic arm, he realizes his vulnerability more. He might start to think more strategically before jumping into battles. For example, in a fight, he won't just rely on his brute strength but use the unique features of his prosthetic arm to his advantage.
One interesting fanfic could be 'Naruto's New Path with a Prosthetic Arm'. In this fic, Naruto might struggle at first to adapt to the prosthetic arm but then discovers new fighting techniques that are unique to his situation. It could show his journey of self - acceptance and growth with this new addition to his body.
One storyline could be that Naruto gets the prosthetic arm after a particularly tough battle where he loses his original arm. He then has to learn to fight all over again, and this time, he combines his old skills with new ones enabled by the prosthetic. For example, the prosthetic arm could have special compartments to store kunai or other tools.
In my opinion, Edward Elric from 'Fullmetal Alchemist' has a great prosthetic arm. His arm is part of his alchemy abilities. It can be transformed and used in combat and alchemy experiments. It's not just a replacement for his lost arm but an important tool that he has learned to master and use in various creative ways.
One plot idea could be Naruto using his prosthetic arm as a symbol of his past battles and how he overcame his injury. It could have special abilities like being able to store chakra more efficiently, allowing him to perform new jutsu. Another idea is that the prosthetic arm is a gift from an unexpected ally, which then leads to a whole new set of adventures and relationships as Naruto tries to figure out the true purpose of the arm.
One of the best prosthetic arms in fiction is Luke Skywalker's in Star Wars. It's highly advanced, allowing him to perform complex actions like fighting with a lightsaber. It's also integrated well into his body, almost as if it's a natural part of him.
It can make him more empathetic. Since he has experienced loss (his original arm) and now has to adapt with a prosthetic, he might understand others' pain better. For instance, when he meets a disabled ninja, he can relate to their struggles.
One interesting story could be about how Naruto's prosthetic arm has special abilities. Maybe it was created by a powerful ninja who imbued it with the ability to sense chakra from afar. This would give Naruto an edge in battles as he could detect enemies before they got too close.
It might be that Naruto has found a new power or ability that makes the prosthetic unnecessary. For example, he could have developed a new form of chakra control that allows him to function without it. Also, perhaps he is about to engage in a fight where the prosthetic would be a hindrance rather than a help, like if he needs to be more agile and the prosthetic is weighing him down.