Well, if you have the ability to, you could perhaps offer to help with the sorting. Maybe create a guide or something to show how it should be sorted correctly. For example, if it's sorted by genre and it's in the wrong genre, you can detail what elements make it belong to a different genre.
You can search by specific keywords related to the correct sorting criteria. If it should be sorted by a particular theme, use that theme's keywords. Also, check the author's other works as they might be more consistently sorted.
Another plot could be that Draco's sorting into Gryffindor causes a rift in his family. His parents are disappointed, but Draco finds a new family among his Gryffindor housemates. He could also have a love interest in a Gryffindor girl, and they have to overcome the house rivalries to be together. The story could explore how Draco changes and grows in this new environment.
One interesting plotline could be Hermione struggling to fit in Slytherin at first. She's used to the values of Gryffindor, so being in Slytherin where ambition and cunning are prized in a different way would be a big adjustment. For example, she might have to deal with the initial suspicion from her Slytherin housemates who are not used to having a 'Mudblood' among them. But as time goes on, she could use her intelligence to show them that she belongs there and maybe even change some of their views on blood purity.
One idea could be that Draco, being in Ravenclaw, uses his intelligence to re - evaluate his family's pure - blood ideology. He might start to question the old ways and form new friendships with Muggle - borns or half - bloods in Ravenclaw. Another could be that he becomes a rival to Hermione in academics, leading to a different kind of relationship between them than in the original series. He could also be part of a group in Ravenclaw that is dedicated to researching ancient magic and discovers something that changes the wizarding world.
Well, at first Harry would be very suspicious of Draco. But as Draco shows his Gryffindor side, Harry might start to trust him more. They could become reluctant allies, especially when facing a common enemy.
Hermione's character development could involve her learning to balance her traditional values with the new ones in Slytherin. She might start to value self - preservation more, as it is a trait often associated with Slytherin. This could make her a more well - rounded witch, not just relying on her Gryffindor - like courage all the time. Draco, on the other hand, could become more empathetic. Seeing Hermione face the challenges of being in Slytherin as an outsider could make him realize how wrong some of his previous actions were, and he could grow to be more inclusive.
If Draco was sorted into Ravenclaw, his character would develop in a very different way. His sense of self - worth would no longer be tied so much to his family name and pure - blood status. He'd have to rely on his intelligence and wits. He might become more empathetic as he's exposed to different types of students in Ravenclaw. He could start to question the bigotry he was taught at home and become a more open - minded wizard. Also, his rivalry with Harry Potter could take a different turn. Instead of being a pure - blood supremacist - driven rivalry, it could be more about academic competition or different views on how to use magic for the greater good.
At first, it might be less hostile. Since they're in the same house, Draco might see Harry as someone he can influence or befriend. Harry, on the other hand, would be cautious but also curious. They could end up having a sort of begrudging respect for each other as they realize they both have complex personalities.
In a fanfiction where Regulus Black is sorted into Hufflepuff, he might face a lot of prejudice from his own family. They could be disappointed that he's not in Slytherin. But in Hufflepuff, he finds true friends who support him. He could use his intelligence (which is often associated with Slytherins) to help Hufflepuff in things like academic competitions. This would show that being in Hufflepuff doesn't mean he lacks the traits that other houses value.