The class sizes don’t seem to make sense.
When you start paying too much attention to Harry Potter, a lot of things start to fall apart. While a lot of things were well planned, there were a few things that were not. The size of the classes is one of them.
There are numerous discrepancies in this article. The Gryffindor dorm room, for example, is rather modest given how large their table is at the end of each year. Also, how can the world’s most important wizard school be so little when other wizard organisations (such as the Ministry of Magic) are enormous?