As far as this theme goes, the book is one of many, nothing special. Heck, for a while, almost every Disney movie carried exactly this trope. What makes Harry Potter stand out is the creativity of J. K. Rowling. Is she a prose-master? Not exactly. But as fantasy lit for kids goes, the writing is intelligent, yet fast-paced and readable. The characters, both major and minor, are vivid, sympathetic, and brilliantly developed. Rowling's world-building skills are also incredibly good. The profusion of funny incidental items she introduces into the story, from the Nimbus 2000 flying broom to Bertie Bott's Every Flavor Beans help add a certain quirkiness that is undeniably charming.
However, my opinion of the value of mainly escapist fantasy literature has changed substantially in the 25-odd years since I was 12. In the interim, I have realized that life itself is interesting enough and that if you're easily bored with it, it's most likely because you're a boring person. Therefore, for a book of this sort to have some real value--especially for younger readers--it needs to teach them something good and noble about real life outside of Hogwarts Academy. It is on this point that Harry Potter and the Sorcerer's Stone stumbles. My main criticism of the book can be summed up in one sentence:
"Hermione had become a bit more relaxed about breaking the rules since Harry and Ron had saved her from the mountain troll, and she was much nicer for it." (pg. 181)Upon finishing the book, it was that sentence that stuck with me. To paraphrase the apparent message: rules are for stuck-up prigs, and if you want to get anywhere and have people like you, you need to break 'em with abandon, even if you lack the experience necessary to fathom why the rules are there in the first place. Again, this is a standard Disney-style trope that I have always hated. And to make matters worse, Harry and his friends are rewarded repeatedly in the aftermath of their rule-breaking. It was a disappointment to me (and a literary mistake, if I may be so bold) at the end that Harry and Gryffindor were awarded enough points at the last possible second to give them the House Cup. It actually made me feel bad for Slytherin--as a Philadelphia sports fan, I know that feeling of being ripped off by the officials all too well.
This annoying element is mostly balanced out, however, by the overriding sense of good and evil that is present throughout the book. "There is no good and evil," says the slavish and simpering Professor Quirrell, servant of the evil Voldemort, "only power and those too weak to seek it" (pg. 291). To its credit, Harry Potter and the Sorcerer's Stone is not a relativistic book. Evil is well defined. Good is also presented, though perhaps a bit more vaguely and occasionally with a Machievellian undercurrent--in the fight against evil, the rules are not all that important. Love, particularly familial and self-sacrificial love, is also extolled.
Having only read the first book in the series, I'll give Rowling the benefit of the doubt when it comes to the rule-breaking stuff. Perhaps she's got a reasonable explanation for it in the future volumes. I'll be looking for it as I read volumes 2 through 7. I must say, though, that there are plenty of fantasy lit books for young people out there that do a much better job of tackling the subject of good and evil than this one, among them Niamh and the Hermit and Dream of Fire.
As for the common criticism that the Harry Potter series is a gateway to the occult, for a well-catechized young person over the age of 13 or 14, this book should cause no problem in that regard. If the reader is an impressionable child of 8 or 9 who is not well-catechized, I would be a lot more cautious. If they must read it, I would strongly encourage a parent to read along with them.