Another interesting plot is if the reborn character has a different power in addition to Sasuke's Sharingan. This new power could create unique battle scenarios and interactions with other characters. They might use this power to gain more influence within the ninja world faster than Sasuke did in the original story.
A plot could also revolve around the reborn character trying to prevent Sasuke from going down his dark path. Since they have an outsider's perspective, they could use their knowledge to guide Sasuke in a different direction, which would greatly change the overall Naruto storyline.
One plot idea could be the reborn character having all of Sasuke's memories from the start. This would allow them to quickly adapt and perhaps change some of the events that Sasuke went through in the original story. For example, they could avoid some of the more tragic moments or make different choices regarding his relationships.
One idea could be a fanfiction where Naruto and Sasuke have to team up again to face a new threat from an ancient evil that has been awakened. They have to put aside their past differences completely and combine their powers in a new way. For example, Naruto could use his Sage Mode along with Sasuke's Rinnegan to perform a super - powerful jutsu.
One plot idea could be that Usagi, with her lunar powers, gets transported to the Naruto universe. Sasuke, initially suspicious, gradually realizes she can be an ally. They team up to fight a common enemy that threatens both their worlds.
A great plot could be that Sasuke discovers a long - lost Uchiha technique and he and Sakura try to figure out how to teach it to their child in a safe and ethical way. It could involve a lot of family discussions and also some cool ninja training scenes. Or perhaps a story where the Uchiha family has to host a big shinobi gathering and Sakura has to deal with all the preparations while Sasuke is out on a mission, and then he comes back just in time to help her out.
She could be a healer in the fanfiction. In the world of Naruto, healers are very important. Sasuke's sister OC could use her healing skills to help not only her friends but also enemies in need. This would create a lot of interesting situations where she has to make moral choices. For instance, should she heal a ninja from an enemy village who has information that could save her village? It would also put her in a unique position within the Uchiha clan as a valuable asset.
A really interesting plot would be Naruto, reborn as Sasuke, trying to prevent the events that led to Sasuke's departure from Konoha in the first place. He would use his knowledge of the future and his Naruto - esque determination. He might also struggle with Sasuke's memories and emotions, which could create internal conflict. For example, when dealing with Orochimaru, he would have to fight the urge to follow Sasuke's original path while also trying to outwit Orochimaru with his own Naruto - like wits.
A plot could revolve around their family planning. Maybe Sakura wants to start a family right away, but Sasuke is hesitant due to his past and the dangerous world they live in. This creates tension between them, and they have to work through their differences and communicate better. They could also face external pressure from the village elders regarding their family plans.
One interesting plot idea could be Sasuke and Sakura going on a dangerous mission together where they have to rely on each other completely. This would strengthen their bond and lead to some deep emotional exchanges.
Maybe the OC reborn as Sasuke has some special powers from their previous life that they combine with Sasuke's natural abilities. This could lead to new and exciting jutsu creations. They could also use their knowledge of future events to help Sasuke form better relationships with his teammates, like Naruto and Sakura, which would in turn affect the overall story arc of Naruto.
One unique plot idea could be Sasuke traveling to an alternate universe where the Rinnegan has different powers. He might have to team up with versions of his former enemies to face a new, greater threat. For example, working with Orochimaru to stop a rogue group of ninja who are misusing the power of a corrupted Rinnegan.
One idea could be that Sasuke and Hinata are sent on a secret mission together to retrieve a powerful and ancient ninja artifact. During the mission, they have to rely on each other's skills and gradually gain respect for one another.