Well I didn't mean to come off as the defendant for the case of Brother Card vs. Ms. Rowling but I must say he is right on a few points. As a literary analyst it's hard to read her works as anything either original or groundbreaking, but they are what they are--delightful books that are genuinely exciting, well-written, and unique. But her desire to maintain a semblance of control over her works demonstrates that she really doesn't get how the literary community works sometimes.
I like to compare her to Tolkien (Uh-oh, here we go on one of the Captain's philosophical academia posts--you can stop reading now if you're bored), if only because the contrasts are so interesting. Tolkien was eager for people to expand and further the history and scope of Middle Earth. He hoped it would inspire music, poetry, and literature, thus enriching the lives of everybody who contributed to his creation. He left many things unexplored so that others could discover them, unexplained so that others could reveal them, and unfinished so that others could complete them. He did not view himself as the warden of some secluded world which only he had the right to access--he wanted his world to be a haven of creativity, innovation, and art. And that is what made his works so revolutionary, so vast, and so profound.
By closing off Harry Potter's world to other creators, she's hindering the very pulse of artistic inspiration and creation. People feel that by letting others in on it, she's getting the short end of the stick for all her work. Yet no matter how many imitations there may be, people will always recognize the hand of a real master. Many people imitate Michelangelo, yet never surpass him. People will try to write like Shakespeare, but they will never equal him. I could devote my life to bettering Beethoven, but I'll never approach him. If she was really confident in the quality of her works, these other issues wouldn't matter. True art isn't a matter of credit--it's a matter of creation. Whether or not people try to imitate you is really inconsequential when your only concern is the betterment of your art. Would she have made this case when she began the books, and only wanted to publish the story that she loved so much? No. But I think she's lost sight of the story in favor of the sales. And I pity that.