Perhaps the author is trying to be different. Since so many fanfics already focus on Harry and Quidditch, they choose not to.
It could be that the author thinks Harry has other more interesting aspects to explore than his Quidditch side. His battles against Voldemort or his friendship with Hermione and Ron could be more appealing to write about.
Well, it could be that there was a personal vendetta against Harry at the Quidditch World Cup. Some wizard or witch who had a grudge against him might have started something, and Harry had to fight back. He is known for not backing down when faced with a threat. Also, if there was a plot to steal the Quidditch World Cup trophy, Harry would fight to prevent that from happening as he values fairness and the importance of the sport.
One possible reason could be that he is wrongly accused of using dark magic. In some fanfictions, the Ministry of Magic might be more corrupt or easily influenced, and they could frame Harry for something he didn't do, leading to his expulsion.
One reason could be that he has a change in motivation. Maybe he realizes that good grades can help him achieve his long - term goals, like becoming an Auror. So he starts to put in more effort into his studies.
Ron could be mad because he has some unspoken feelings for Hermione that he's not fully aware of yet. When he sees her at Quidditch, enjoying herself without him, it stirs up these confusing emotions inside him. Additionally, if there were rumors going around Hogwarts about Hermione and someone at Quidditch, Ron, being the hot - headed person he can be, might get angry without even verifying the rumors.
Perhaps there is some external threat or danger related to Quidditch. Maybe there is a dark wizard who is targeting Quidditch players and Harry doesn't want to put himself or his friends in danger. He has already faced so many threats in his life that this additional risk related to Quidditch might be too much for him.
Well, perhaps it was because of a conflict with a powerful figure. Maybe she had a huge argument with the Headmaster or someone from the Board of Governors. If she strongly opposed a decision that the higher - ups were very much in favor of, it could lead to her dismissal. For instance, if there was a plan to cut down on certain magical subjects that she thought were essential for students' education. And in a fanfic world, there could be some made - up reasons too, like a mysterious prophecy that said her presence at Hogwarts would bring some great danger, so they fired her to avoid it.
One way is they could let Harry choose the next Quidditch match location. This gives Harry some power and also shows that they trust his judgment. It would be a great adventure for the whole team too.
Another possibility is that the fanfiction writer wants to explore a different side of their relationships. By having Hermione and Ron hurt Harry, it shows the complexity of human (or in this case, wizard) emotions. It could be a way to show that even the strongest friendships can have cracks and that mistakes can be made. It also allows for character development as Harry has to deal with this new situation, and Hermione and Ron may later realize their mistakes and try to make amends.
Well, it could be that Harry, at that moment, saw Draco not as his rival but as a fellow student. In the wizarding world, Quidditch can be a very dangerous sport. Harry might have thought about how his friends would feel if he were in Draco's position. Also, Harry has a heroic streak. He might have instinctively jumped into action without really thinking about who it was he was saving. His first impulse could have been just to stop a potential disaster from happening on the pitch.
One aspect of a fanfic about Harry as a Quidditch star could be his impact on the wizarding world outside of Hogwarts. His popularity as a Quidditch star could lead to him being invited to various wizarding events as a guest of honor. He could use these opportunities to advocate for better conditions for house - elves or other marginalized groups in the wizarding community. This would show that his fame isn't just for his own glory but also for the betterment of the wizarding world as a whole.