Another aspect could be that the fanfiction delves into how Kushina's presence affects Naruto's relationships with others. For instance, his relationship with Sasuke could be different. With a strong maternal figure in his life, Naruto might be more stable emotionally and be able to approach Sasuke in a more understanding way, which could potentially change the whole dynamic of their rivalry and friendship.
Perhaps Naruto finds a way to travel back in time and prevent Kushina's death in the first place. He could use his Sage Mode or some other special ability to manipulate time. And then, by changing the past, he effectively'revives' her in the present. In the Naruto universe, there are all kinds of crazy powers, so time - travel isn't completely out of the question.
In some fanfictions, Kushina was sealed into Naruto through a complex jutsu. It might be a modified version of the sealing jutsu used to seal the Nine - Tails. The process could involve special incantations and chakra manipulations.
One common plot is Kushina finding Naruto in a different time or dimension. For example, she might end up in the future where Naruto has grown up and she gets to see the kind of person he has become. It's an emotional and interesting concept as she gets to witness all his achievements and the challenges he has overcome.
Jiraiya could also be one of the main characters. He was Naruto's mentor and had a connection with Kushina's family. He could play a role in helping them adjust to the time travel and also use their knowledge to his advantage in some ways, like getting intel on future threats.
Maybe she's been possessed. In some fanfictions, characters can be taken over by dark forces. So Kushina could be under the control of some evil entity and that's why she hurts Naruto.
Iruka could be one of the characters. He has always been important to Naruto, and he might try to help Naruto or at least be concerned about his exile. Kakashi could also appear. He has a connection to Naruto and might be conflicted about the situation. And then there are Naruto's friends like Sasuke and Sakura. Sasuke might understand Naruto's feeling of being an outcast more than others, and Sakura could be torn between her loyalty to the village and her friendship with Naruto.
Naruto would become more confident in his abilities. With Kushina's training, he would have a better understanding of his Uzumaki heritage and the power that comes with it. This new - found confidence would show in his battles and his interactions with others.
In a fanfiction, Kushina could want Naruto to master a unique jutsu that she had always dreamed of but was unable to achieve herself. This could be a jutsu that combines the power of the Uzumaki clan's sealing techniques with some other element, like wind. And she would be guiding Naruto in his journey to master it, through some kind of spiritual connection.
Kushina's angst could also stem from her past as a Jinchuriki. In fanfiction, she could be haunted by the memories of being ostracized or feared by the villagers. This could lead to her having internal struggles and moments of deep sadness, especially when she thinks about how her son Naruto might face the same fate.