Just a kid? More like a kid who makes friends in a magical world while learning from some wise guy and trying to get free from his uncle's abuse while having romantic relationships and journeying all over England trying to fight off the greatest dark wizard of all time.
Honestly, there's like 1000 other complex characters.
I honestly think Harry Potter will be remembered as a classic. It is written with a cleverness and wit that appeals to all ages, not just teens, and anyone can get absorbed into that world. I mean, just name one mentally sane person who doesn't want to go to Hogwarts. If it doesn't become a classic...well, it was better than fluff which are only remarkable because the author lived a long time ago.
OK, so clearly the story appealed to you, but you have to be utterly insane to think such writing style and such a world of complexity with life-like character development hasn't been done before with countless numbers of books.. I mean from what I have seen over the years, despite Harry Potter's popularity, Lord of the Rings for example gets more praise among the literature world. And for the most part, no reputable literature analysis list includes Harry Potter among the best novels. Again, I'm not saying JKR is a bad writer, not at all, nor am I saying the stories were bad themselves, because that certainly isn't the case, however, I am saying that what has been done with Harry Potter has been done many times before and her stories just happened to catch fire dramatically. They are like popular and good pop songs: very catchy, caught a big break and attention, many people may like it, but it isn't like there is truely something new going on when you compare it to other songs.
Perhaps you should broaden your book horizons a little bit and maybe read some classics?