J.K. Rowling has stated absolutely that Harry Potter is the last book. But Rowling now admits that she hasn’t written of the idea entirely, and perhaps at a later date she may return to writing Harry Potter book – which you KNOW they will make a movie out of even if it is 10 years from now.
Washinton Post quotes J.K. Rowling:
Though she said she doesn’t plan to write any offshoots of the Potter series, she didn’t rule it out “maybe 10 years from now,” depending on how she feels. But she told one child she does want to write more books.
“Yes, I do, and I am,” Rowling said. “I’m quite sure in the not-too-distant future I will bring out another book.”
This is going to be a big shoe to fill for JK to follow up on Harry Potter with another book. But she does have a built in fanbase that will buy it just because her name is on it.
Her writing did mature as the seven book series grew, which is the most fascinating thing about Harry Potter. As its readership got older, the writing grew with them as did the main characters of the book.
The inevitable translation of those successful books to film have suffered similar problems other book adaptations have seen, but all in all the films are pretty faithful to the books, and are clearly leaping her literary fame to the point of an entire theme park area dedicated to her fabrications.
Should she write a new story that is as well received, movies will follow. But I would like to see her eventually return to the Harry Potter world. There is so much that is introduced in the books that could branch out into new stories. Just like the Star Wars Novels, they should license out the brand, and allow others to write stories from other parts of the world, or other jobs.
Just the Aurors alone would make a great action adventure story as they hunt down magical criminals. Not everything has to revolve around Hogwarts.