If we consider a gender - swapped Kurapika in a fanfic, it could have a significant impact on the story arc. For example, if Kurapika was female, her emotional journey might be perceived differently. Her anger and determination for revenge could be seen as more of an underdog story, as in some fictional universes, female characters are often underestimated. This could add more depth to her character as she overcomes these biases.
A really interesting plot could be set in an alternate universe where Gon and Kurapika have different roles. For example, Kurapika could be a carefree adventurer like Gon usually is, and Gon could be more focused on revenge like Kurapika. This role - reversal would create a whole new dynamic between them and could lead to some really unique storylines.
In fanfiction, their relationship can be deepened if they exchange stories about their pasts. Gon could tell Kurapika more about his father, and Kurapika could open up about his clan. This would create a more intimate connection between them.
The Hunter x Hunter manga is unfortunately not complete. The author has faced various issues that have led to intermittent breaks and an unresolved storyline.