One idea could be that it explores the power dynamics within the wizarding world without Harry as the chosen one. Maybe other characters step up and new alliances are formed.
Neville is a likely candidate. He has always been brave and has a strong connection to the Gryffindor values. If not for Harry, Neville could have easily stepped into the role of the main character. His growth throughout the series shows that he has the potential to be a great hero.
Perhaps in this fanfiction, Draco Malfoy has a change of heart and is revealed to be the one who can truly end the dark reign. He might be in a unique position to infiltrate the Death Eaters due to his family's connections, and then use that knowledge to turn the tables on Voldemort. His Slytherin cunning could be used for good in this alternative scenario.
One interesting plot could be that Harry discovers new, hidden magical abilities that are not mentioned in the original books. This could give him an edge in fighting the Dark Arts and change the course of his battles.
Harry Potter himself is obviously still very popular as the main character. His growth and development as the Chosen One are often central to these fanfictions.
Ash as the Chosen One in Pokemon fanfiction is a really interesting concept. It gives a whole new layer to his character. He could be given a special Pokemon by some mysterious force that is crucial for his destiny. This Pokemon might be one that no one has ever seen before. His friends would also play different roles, perhaps as protectors or guides to help him fulfill his chosen - one duties. And his battles would become even more epic as he has this greater responsibility on his shoulders.
If Hermione was the chosen one in fanfiction, it could lead to a whole new exploration of her character. Maybe she'd discover hidden powers or form unexpected alliances that would shape the course of the story in exciting ways.
The features of the Chosen One included a broad and flat forehead, deep eyes, bright eyes, a straight nose, well-defined facial features, neat teeth, perfect lips, smooth skin, a confident smile, elegant and calm behavior, intelligent and independent thinking, and a gentle and kind heart. These characteristics made the Chosen One show extraordinary charm and advantages in both appearance and inside.