In many Harry Potter fanfics, Albus Dumbledore is often still considered one of the best. His wisdom, kindness, and powerful magic made him a great leader in the original series. He was able to guide students, deal with dark magic threats, and keep the school running smoothly.
Another possibility is that it could be Severus Snape in an alternate universe where he becomes headmaster of a different school. He was a complex character at Hogwarts, and seeing how his skills and personality would play out in a different educational setting would be very interesting. He might be more open - minded in a new environment or face different challenges that would test his loyalty and abilities.
Another possibility is McGonagall again. She has been an excellent teacher and deputy headmistress for a long time. Her experience and strict but fair nature would ensure the smooth running of Hogwarts. She already has a great relationship with the students and faculty, and could continue to uphold the school's traditions while also making some positive changes.
A great plot could be that Harry decides to open Hogwarts to students from all over the world in a more inclusive way. However, this causes some cultural clashes among the students and staff. He has to find a way to make everyone feel welcome and at the same time maintain the school's traditions. Also, there could be a plot where a mysterious prophecy about Hogwarts is revealed, and Harry as headmaster has to figure out how to prevent its doom.
Well, it could be that Harry as headmaster has to deal with a new generation of students who idolize him. He would have to balance being a role model and an authority figure. Maybe there would be a plot where some students try to use his name to get away with rule - breaking, and he has to set them straight. Also, he could start new Quidditch traditions or tournaments to boost school spirit.
A popular choice could be a character like Sirius Black. If he had survived, he could have become headmaster with his rebellious yet caring nature. He would bring a different kind of leadership to Hogwarts, one that is more in tune with the students' desires for change and adventure.
Harry is the central figure. But there could be new characters introduced as students or staff. For example, the children of the original characters could be main characters in their own right. Ginny Weasley, Harry's wife, might also be prominently featured, perhaps as the Quidditch coach or in charge of some other aspect of school life. Additionally, old professors like McGonagall could still be around and be important characters.
In my opinion, Dumbledore would still be a great headmaster in fanfiction. His wisdom and experience are invaluable. He always had a deep understanding of the students and was able to guide them through difficult times. He also had a great sense of humor and was very approachable despite his great power.
One plotline could be that this non - Hogwarts headmaster comes to Hogwarts on an exchange program. They bring their own unique magical curriculum and start to change the way students think about magic. There could be conflict with the traditional Hogwarts professors who are resistant to change.
If the new headmaster was someone like Neville, he might focus on making the school more accessible to students from different backgrounds. He could also introduce more hands - on learning in Herbology, perhaps with a new greenhouse dedicated to rare and dangerous plants for advanced students to study.