the author just wants the 97.5% of the population too brain dead to accomplish anything in life to feel like they can do shit too.
contrast harry to a character who is actually talented, ie dumbledore. when he fought, he used tons of different kinds of magic, he was identified in school as being gifted as was grimmelwald. Harry probably learned many practical spells that we dont learn about like how to cook with magic or clean or do stuff like that but in terms of offensive magic hogwarts avoided that. Remember krum's school, eh I forgot the name but krum wasnt even that great of a wizard but it is mentioned that he knew some varied magic and even had some cleverness to it. Harry is a loser. He is the kid who scrapes by not by their intelligence but because the system wants to make sure he can get a job after school. His dream of being an auror was rediculous and he sort learned through experience a few tricks.
Its a shame that rowling didnt think to give harry voldermort's giftedness even though they shared so much else =/
naruto should also be one of the strongest ninjas in the whole damn show but he gets his ass beat until the kyubbi gives takes over.