mickeytopogigio saidIf Harry, Hermione or Ron were one of the villians, that would rock.
That would be awesome, but it would absolutely never happen.
Harry Potter stopped being a literary being a long time ago. It became a commercial juggernaut and stopped being an entity of literary creativity.
This is the reason Harry Potter didn't die in the last book. I bet you ANYTHING Rowling's publishers strongly pushed her into not killing him, perhaps even at the threat level. Why? Because Harry Potter is a money maker in every sector. Books, films, toys, clothing, video games, board games, action figures. The manufacturers of these absolutely BANK that little kids will buy them and play with them, pretending to be Harry Potter, making up new little stories and plot lines of their own.
If Harry Potter had died in the final book, in a sense he would have been dead since the beginning. Imagine for example a mean older brother telling his little brother "YOU KNOW HE DIES IN THE END". Little kid cries, and doesn't see the point of playing with his little Harry Potter action figure.
The series, as a literary creation, doesn't need more books. But EVERYONE connected to the publishing industry knows that if Rowling wrote another book it would be an immediate gold mine for everyone involved. Instant money maker. Hell I can even bet you they'd line up a movie script for it as soon as it came out and it would be a fucking successful movie. And when you have guaranteed money makers like that then that's all that matters. No room for literary or creative logic.