All I can say is I don't think my niece will be reading HP7 for a year or two due to a bit of profanity which was really unexpected considering the target audience still young.
The so called "Carpet Book" was real. Rowling was never a great writer, but she never gave the impression she was going to seriously jump the shark. It remains to be seen whether or not the book will actually tie up the loose ends she said it would, but it doesn't look promising.
It's almost like she hired a ghost writer.