Itachi's teaching style, being calm and strategic, would likely have a profound impact on Naruto's growth. He might teach Naruto to be more patient and observant. For example, Itachi could show Naruto how to analyze an opponent's moves before acting impulsively, which is a big change from Naruto's usual head - first approach.
One unique training method Itachi might use is teaching Naruto through illusions. Itachi is a master of genjutsu. He could create illusions that simulate real - life battle scenarios with various levels of difficulty. This would allow Naruto to practice his combat skills and decision - making in a safe yet challenging environment.
At first, Naruto might be a bit wary of Itachi because of his reputation. But as Itachi starts to teach him, Naruto would see his kind heart and wisdom. Their relationship could develop into a deep mutual respect. Itachi would see Naruto's potential to change the ninja world for the better, and Naruto would come to understand Itachi's sacrifices. They might start as teacher - student, but eventually become like family, with Naruto looking up to Itachi as a mentor and a friend.
In the fanfiction, Naruto's new sensei could be a mysterious figure who has ties to the Sage of Six Paths. This person might have been waiting for the right time to appear and train Naruto. They could possess knowledge about the origin of chakra and how to fully unlock Naruto's power. It could also be someone who was once an enemy but has now changed their ways and wants to use their skills to train Naruto for the greater good of the ninja world.
There's a chance that Naruto's new sensei could be a self - taught ninja who has developed their own unorthodox style. This person sees Naruto's ability to think outside the box and wants to refine that in him. They could introduce Naruto to a new way of looking at chakra control and combat strategies that are completely different from what he has been taught so far.
A great plot could be Itachi teaching Naruto how to control the Nine - Tails' chakra in a completely different way than Jiraiya did. Since Itachi has such a deep understanding of chakra and its nature, he could offer unique insights. Also, there could be a story where Itachi and Naruto are forced to team up against a common enemy that is using an ancient and powerful jutsu. In the process, Itachi passes on some of his Uchiha clan's wisdom to Naruto. And perhaps, Itachi could help Naruto deal with the loneliness that often comes with being a jinchuriki, as Itachi has also felt isolated in his own way.
In some Naruto fanfictions, Minato could potentially be Kushina's sensei. He was highly skilled and had a connection with her, so it's a plausible idea in fan - created stories.
I think Orochimaru would be the most unexpected sensei. Usually, he's seen as a villain, but in a fanfiction, if he were to train Naruto, it would be extremely unexpected. He has a vast knowledge of jutsu, especially forbidden ones. He could teach Naruto some very powerful and unique abilities, but at the same time, Naruto would have to deal with Orochimaru's morally ambiguous nature.
Tenten would also be an interesting choice. She could focus on weapon - based combat training for Team 7. Since she has extensive knowledge of all kinds of weapons, she could introduce new and unique weapon techniques to the team.
One possible replacement could be Gai. He is a strong and enthusiastic ninja who has a friendly rivalry with Kakashi. He could bring a different kind of training style to Team 7, focusing more on physical and direct combat training, which would contrast with Kakashi's more laid - back and strategic approach.