The plot implications could be huge. It could create a new dynamic between Naruto and the Uchiha clan. Naruto would have a part of Uchiha heritage, which might make some Uchiha more accepting of him. Also, it could lead to new alliances as other villages might see Naruto as an even greater threat or an even more valuable ally. And in terms of character development, Naruto would have to deal with the new power and the potential darkness that comes with the Sharingan.
Naruto might give Itachi some traditional Konoha food as a gift. Since Itachi has been away from the village for a long time, he might miss the taste of home.
This would be a huge change for Naruto. Firstly, the Sharingan's ability to see chakra flow would let Naruto analyze his opponents' weaknesses more accurately. He could potentially use this to improve his Rasengan or develop new jutsus. Moreover, in terms of combat, he could enter genjutsu battles on a more equal footing, which was something he previously struggled with due to his lack of natural genjutsu skills.
The story could progress in many ways. For one, Sasuke might be filled with guilt for receiving Naruto's eyes. This guilt could drive him to become a better person and fight for the things Naruto believes in. He may also use the new vision to uncover secrets or powers that were previously hidden. On the other hand, Naruto, without his eyes, could develop other enhanced senses or abilities, and together they could form a new kind of partnership. They could also face challenges from those who oppose the idea of Naruto sacrificing so much for Sasuke.
Well, the plot could start with Itachi realizing that Naruto is the key to the future of Konoha and the ninja world. So, he gives Naruto his Sharingan. Naruto then has to deal with the new power. He might start having visions related to Itachi's past, which could help him understand the Uchiha - Senju conflict better. And this new knowledge could influence his decisions in future battles and political situations in the ninja world.
In the fanfiction scenario where Madara gives Naruto his eyes, Naruto's abilities would transform. Firstly, the basic Sharingan abilities would improve his reaction time and perception. He could analyze his opponents' moves better. With the potential for the Mangekyo Sharingan, he could gain unique and powerful techniques. For example, if he got a fire - based Mangekyo ability, he could combine it with his own Rasengan or other wind - based jutsus to create new and more powerful attacks. This would not only make him stronger in battle but also give him new ways to protect his friends and the village.
A simple plot could be that Itachi entrusts Naruto with his Sharingan because he believes Naruto can use it to bring peace to the ninja world. Naruto, being the kind - hearted person he is, accepts the responsibility. He starts training with Kakashi to understand and master the Sharingan's powers. With the Sharingan, Naruto can anticipate his opponents' moves better and uses this advantage in battles against powerful enemies like Pain.
I'm not sure about a specific one off - hand, but you can check out fanfiction websites like Fanfiction.net or Archive of Our Own. Just search for 'Itachi gives Naruto power' and you'll likely find a bunch of different stories. Some might focus more on the action aspect, while others might explore the emotional side of Itachi's decision to give Naruto power.
One possible reason could be that his eyes hold a special power that he doesn't want others to discover easily. For example, it might be a new type of Sharingan or a unique ability related to his Uzumaki heritage that he needs to keep secret to protect himself or those around him.