The Internet is full of fan theories. Some of them are cool and plausible, and some of them are “Ron is a time-traveling Dumbledore, please discuss.”
Now, I would first like to say that I think the Harry Potter books are very good as they are. Do I have my quibbles? Of course I do. For one thing, there wasn’t NEARLY enough Oliver Wood for my liking. For another, Hermione never used the Time-Turner to take more naps, not even once. But these are minor grievances; I can overlook them.
What I can’t overlook is that some people—fans, just like you and I—came up with cool and plausible fan theories that not only make sense within the context of the story, but actually improve it. Check your loyalty to JKR at the door and admit that the following ideas could have made a beloved childhood classic that much better.