Nicholas Lezard needs to get a life. I might have failed to get through the first of the Potter books, but I'd never presume to judge Rowling or the level of her craft for such a paltry reason. Who cares if Rowling overuses adverbs to denote her characters' manner of delivering dialogue? Just think of all those gazillion youths, branded forever by "indignantly" or "firmly" or "curiously"! Won't somebody think of the children?
Adult bestselling authors overuse adverbs routinely(oops). Stephen King overuses adverbs and also CAPS LOCK and italics in order to make up for a lack of descriptive power.* I still liked Pet Sematary.
"Some books are meant to be FUN," he said frustratedly.
*Or because, like Rowling, he needs to churn out the next blockbuster by lunchtime, and worrying about silly stylistic points slows down the process.