Interesting article from Will Gompertz on the BBC website, speculating about JK Rowling's future plans for the Harry Potter franchise (http://www.bbc.co.uk/news/entertainment-arts-14081148). Particularly interesting as it contradicts almost everything that Miss Rowling has ever said about extending the Potter-verse with new books.
However, I do agree with Will on one point - she is a writer and therefore she will write. The announcement of the new Pottermore site, which will contain some of the back-story that she has already written, may be one outlet for her creativity in the short-term, but what will she do longer-term?
I know only a little about her story development, but I believe she came up with the Harry Potter idea in a flash, then spent many years honing the story. Whatever else she does will probably follow the same development pattern so I expect nothing new for many years!
One point to Will Gompertz though... "Americans can't get enough of the pre-War Britain and boarding school thing." Pre-war? I'm pretty sure the series is contemporary (Dudley Dursley has TVs and computers). Perhaps more research required?
