In terms of appearance, a female Snape would look different, of course. But more importantly, her self - confidence might be presented in a different way. A female Snape could use her appearance and charm in a way that the male Snape never did, to manipulate situations or gain allies, which would be a significant change from the original character.
In these fanfictions, Snape often becomes more self - reflective. He starts to realize the full extent of his actions and how they've affected others. For example, he might come to see how his treatment of Harry was unfair. He also becomes more open about his emotions, which was something he always hid before.
Snape's character often becomes more open - minded. In many such fanfictions, being around the Marauders, who are generally more carefree and adventurous, forces Snape out of his shell. He starts to see things from different perspectives, rather than just being the brooding loner he was originally.
Snape's character changes in his relationship with others too. He becomes more involved with the Hogwarts community as he is now responsible for Harry. He might start to collaborate more with other teachers, like McGonagall, who he previously had a rather cold relationship with. His attitude towards the students also changes as he realizes that they are just kids trying to find their way, much like Harry. This is a big shift from his usual strict and often unforgiving self.
She could also be more perceptive of social hierarchies in a different way. Girls in the wizarding world might be subject to different expectations. Snape as a girl might use her femininity to her advantage, perhaps by being more charming or manipulative in certain situations to get what she wants, which is different from the male Snape's more brooding and solitary approach.
In some fanfictions, Severus Snape's character develops by becoming more open - minded towards Muggles. He might start off with his typical wizarding - world prejudices, but through various interactions, he begins to see Muggles in a new light. For example, he could meet a Muggle scientist whose thirst for knowledge reminds him of his own love for potions, and this changes his view.
One interesting genderswap fanfiction could be where Female Snape has a different relationship with the students. Maybe she's more nurturing in a way that challenges the original Snape's harsh exterior. For example, she could form a closer bond with Hermione, seeing her own past self in the bright and studious girl.
It changes the power dynamics. Usually, Snape is seen as an outcast and Hermione is part of the main group. When she trusts him, it gives Snape more of a connection to the 'good side'. For example, the other characters might start to re - evaluate their views of Snape because Hermione trusts him.
His role becomes much more mysterious. He is no longer just a potions master and spy. He now has a connection to an entirely different realm. His actions are not only about the wizarding world's affairs but also about his father Hades' will. He might be involved in preventing some sort of underworld - related catastrophe from happening in the wizarding world.
In many fanfictions where Severus Snape has a baby, it can soften his character. He might become more protective and show a side of him that was hidden before. His priorities shift from just his role in the wizarding world to also including the well - being of his child. For example, he may be less brooding and more open to forming relationships with others for the sake of his baby.
Well, it changes their dynamics completely. Usually, Severus has been somewhat of an antagonist to Harry. But with Harry being pregnant, Severus has to step into a more protective role. He can't just be the strict teacher or the person who is constantly at odds with Harry.