So, apart from your personal opinion of the books/films, do you actually have anything worthwhile to say? Rowling is hardly Voltaire, but then she wasn't trying to be. She has written what have turned out to be a phenomenally successful series of children's books, which have also captured the adult imagination. I have read all of the books several times over and am in the process of reading my way through the series in preparation for the final installment. I assume you're the sort of gentleman who gives me looks of disgust on trains as I sit there reading Harry Potter, a "children's book". How dare I, as an adult, take pleasure in children's literature! What you're not aware of is that after three years of reading naught but legal textbooks, fictional literature in any form is most welcome to my tired brain, and I happen to enjoy the Harry Potter books for their sense of adventure, fun, good versus evil and the very thing that you complain about most: that they are not written in a complicated matter. If I wanted complicated, I'd re-read my Land Law textbook.
You don't like them, that's fine with me, but I see no sense in starting a thread personally abusing those who find pleasure in some light fiction. Apart from which, how you can consider the likes of Maggie Smith as McGonagall and Alan Rickman as Snape "miscast" is beyond me. I'm of the opinion that the casting directors did a sterling job, because the images portrayed for me on screen of the characters bear an immensely close resemblance to the images I have imagined so many times whilst reading the books.