Well, Naruto has had the advantage of learning from many great shinobi over time. He also has a unique bond with his friends which could potentially give him more strength. Minato, on the other hand, had a shorter lifespan to develop his powers. Naruto has had more time to grow and surpass his father in strength.
The fanfic could portray Naruto as having greater physical strength and endurance. Maybe he can take more hits and keep fighting, while Minato might get tired more easily. Also, Naruto's strategic thinking in combat could be shown as superior, allowing him to outwit Minato in battles.
One possible reason could be Naruto's pent - up anger towards Minato for leaving him as an orphan. He might feel that Minato sacrificed himself without fully considering the consequences for Naruto.
One possible reason could be for Naruto's protection. Maybe Minato knew of some great danger that was coming for Naruto and he thought that banishing him would keep him out of harm's way. Another reason might be related to some prophecy or hidden power within Naruto that Minato feared could be misused if Naruto stayed in the village.
One possible reason could be Naruto's independent nature. He has always strived to make his own path and not rely on his father's legacy too much. So in the fanfic, he might refuse Minato to show that he wants to be his own person, not just Minato's son.
Well, in some fanfictions, Naruto might be considered stronger because he has access to more powerful forms and jutsus. He might have mastered the Nine - Tails' chakra in a more advanced way than Minato could. Also, Naruto has trained with many powerful shinobi, which could give him an edge in strength compared to Minato.
Well, it depends on the specific fanfic. Some fanfics might really emphasize Naruto's growth to be on par with Minato in terms of smarts. They could show Naruto learning from Minato's memories or having some sort of spiritual connection that transfers knowledge. However, other fanfics might focus more on other aspects of Naruto's character and not necessarily make him as smart as Minato.
It could be that Naruto is trying to prove himself. He wants to show that he can be as great a fighter as his father. Also, he might have received some training or knowledge transfer from someone who knew Minato well. This could have inspired him to adopt Minato's fighting style. He may also be in a situation where his normal fighting style isn't working, so he turns to Minato's as a last resort.
One possible reason could be fear. If Naruto was 'godlike' in this fanfiction, his power might be uncontrollable and Minato, as Hokage, might feel it's a threat to the village. He could think that Naruto's power could attract too many dangerous enemies or cause destruction accidentally.
One possible theme is family love. The act of Minato tickling Naruto shows the strong bond between father and son, emphasizing the love and care within a family. Another theme could be innocence. It portrays the simple joys of childhood, like the innocent laughter that comes from being tickled by a parent.
In this kind of fanfic, a possible plot is that Minato and Naruto get to spend some normal family time together. They could go fishing, like Naruto used to do with Iruka. During this time, they bond and Minato gets to understand the simple joys that Naruto has in life, which he might have missed out on if he were still alive in the normal Naruto storyline.