Actually, I have read other books which contain wizarding schools, particularly some of them based on Magic: The Gathering (it's been some time since I've read it, but the Ice Age cycle trilogy involves wizarding school, and one of the color-blue stories from the Colors of Magic anthology involves wizarding students at a school).
However, HP differs in that the focus is on the start and progression of the students at a young age (11), where most books involve either teachers, or students at much older age (generally at the age of apprenticeship, which would be around 16-19 or so).
Most of the reason stems from the concept of power levels; it takes great power to overcome great evil. Harry shows that this isn't necessarily the case, particularly in GoF, where his creative use of simple magic during the triwizard tasks (and against LV) could actually be the most effective way to deal with adversity (of course, the REALLY simple solution to the first task; Accio Golden Egg wasn't tried by any of the champions). Harry and friends tend to outsmart their opponents, while their enemies try to overpower them.