If Fem Naruto looks like Kushina in the fanfiction, it can bring a whole new set of relationships. Sasuke, for example, might react differently to her. Maybe he would be more drawn to her because of her resemblance to Kushina, who was an important figure in the village's history. And the Akatsuki might also have different plans regarding her. They could be more hesitant to attack her, or they might be more interested in using her resemblance to Kushina for their own purposes.
Well, it could change things a great deal. For one, Naruto's appearance being like Kushina might make her more of a target in the beginning as those who had issues with Kushina in the past could potentially target her. Also, characters like Minato might be more protective from the start. It could also lead to different reactions from the villagers. Instead of the initial hatred towards Naruto because of the Nine - Tails, they might be more conflicted seeing a resemblance to Kushina, a former villager.