One possible reason could be for the sake of creating a dramatic plot. The disappearance of Naruto might be used to show how the female characters respond to his absence, highlighting their growth and independence. For example, Sakura might take on more leadership roles in the village without Naruto around.
One possibility could be that Naruto is kidnapped by a hidden enemy right at birth. Maybe a rogue ninja group has a vendetta against the Fourth Hokage and they steal Naruto away. This would lead to a completely different story arc in the Naruto universe, with Konoha perhaps not knowing Naruto's true identity and not treating him as the Jinchuriki. It could also mean that Naruto grows up in a different environment, away from the discrimination he faced in the original story, but also without the friends and support system he eventually had in Konoha.
Orochimaru could be a likely main villain. He has always been interested in Naruto's power and body. Maybe he finally devises a plan to kidnap Naruto and use his body for his own reincarnation experiments.
It could be that Naruto sacrifices himself to seal away a great evil. However, his friends don't believe he's truly gone and embark on a journey filled with self - discovery and growth as they try to find a way to bring him back. Along the way, they might encounter other lost souls or forgotten powers that could potentially help in their quest.
Naruto might also initially feel a sense of abandonment. However, his kind - hearted nature could lead him to try and see the good in the situation. He could start to explore the world outside, learning about different cultures and ninja techniques. He may use this experience to become more empathetic towards others who have also faced hardships, and in the long run, this banishment could be a turning point in his life to become an even greater ninja.
At first, Naruto is probably shocked and confused. He might not understand why the village would take such a harsh step just for hurting Sasuke. He may feel betrayed, especially if he thought he had friends and allies in the village.
A possible plot for this type of fanfiction could involve the banished ninja having a secret mission that the village doesn't want to be associated with. So, they banish the ninja to make it seem like they have no part in it. The ninja then has to complete the mission while also dealing with the stigma of being banished.
Well, in a fanfiction like this, it could explore Naruto's sage mode abilities in a new context while he's with Yugito who has also been banished. Maybe they form an alliance to fight against the forces that banished them. They could discover new powers together and change the shinobi world's view of them.
In a 'Naruto and Anko Banished' fanfiction, the story could start with a false accusation against them. This would lead to their banishment. Once exiled, they could encounter new enemies and allies. For example, they might meet a group of outcasts who teach them unique jutsu. This would add new elements to their fighting styles and also change their perspective on the ninja world.