...I have finally jumped on Harry Potter bandwagon. I did not want to fight bookstore crowds, line up overnight, and read a 700-page doorstop in one sitting so as to have a chance to enjoy it before people reveal spoilers. 10 years has been long enough to forget most spoilers I've heard. But the real reason why I didn't get into Harry Potter books when they were still new was that I did not find them very engaging. I tried the first couple of chapters of book 1, and about the same amount of book 2. I got an impression that the fantasy world in Potter series was no more than skin-deep, and instead of diving in and being swallowed by the book's world, I bounced right out.
This time I started with HP2, "The Chamber of Secrets", because I couldn't find HP1 in the library. (Did you think I was going to pay for it? J. K. Rowling is richer than God already.) Yes, the first few chapters still felt superficial. I'll second what was said by a New York Times or Washington Post book critic: magic in the Harry Potter world has a very specialized, domestic character. For example, there is a clock that shows what time each family member had to be home, or a teleportation method called Floo, that lets you travel through chimneys. It's like magic was shoehorned to fit domestic life.
As I got past the first few chapters, the book drew me in -- not because the Harry Potter world acquired a previously unseen depth, but because the events in it galloped at such a crazy pace. The kids were shunted from adventure to adventure without break. And while a fast-paced plot is generally a good thing, in the Chamber of Secrets the plot left no room for observation, reflection, or world-building. Nobody ever paused to think what the events mean not just in terms of predicting the enemy's next step, but also about the laws of the (magical) world that surrounded them. In the best SF or fantasy books events are just clues that point towards bigger, unseen things; by pausing to reflect, characters attain a glimpse of a deeper order of the world. I saw nothing like that in the "Chamber of Secrets". There was no strangeness there. All the "magic" fit so neatly with the mundance understanding of the world, that there was not a moment where I went, "this is odd, I don't understand this". In other words, the good ole sense of wonder was missing from the Harry Potter world.
It was also a bit disappointing that at crucial moments, such as Harry's fight with Tom Riddle, some magic artifacts appeared in the right time and the right place arbitrarily, with only a flimsy explanation.
One might say that oddness and strangeness is neither appropriate nor necessary in a children's book; but I disagree. (As an aside, I've wondered if any book with a teenage protagonist is automatically a Young Adult book. Probably not. Philip Pullman's "His Dark Materials", with its 11-12 year old protagonists, is definitely not a book for 11-12-year-olds, because of the complexity of its subject matter.)
Eventually though, the "Chamber of Secrets" drew me in, and so did the third book, "Prisoner of Azkaban", which seemed better written and more engaging. The pieces fit together better. Here we finally get glimpses that the wizarding world has a fascinating history, steeped in adult drama. It's still not high-concept worldbuilding that I like in speculative fiction, but it's something.