So, J. K. Rowling has written seven increasingly long novels, plus two short supplements, describing in considerable detail Harry Potter's life, world, history, family and friends. Bizarrely, there are people who are unsatisfied with this, who are even now, less than a week after the publication of a 600-page book, demanding to know what happened next, begging for further explanation of plots and characters, and harassing her to pen a 'Potterpedia' which, in order to satisfy some of these vultures will need to be the size of the Internet.
But the last thing I want, as a reader, is for the author to supplement her story with an endless catalogue of the ideas she had which didn't make it into the books because they weren't relevant or necessary for the story to be told. I didn't much care for the epilogue, but in many ways it came as a huge relief. The first time I heard that JKR was planning such a thing, it was in such a way as to make me fear we would have every character's future life spelled out in tedious detail. At least we were spared that. So why, today, do we need to learn that Ron and Harry will be Aurors (which seems incredibly unlikely to me) and Hermione a lawyer (really? After what she said in DH?) I, for one, feel completely free to disregard any and all information given by JKR in an interview.
It's a hard fact for some to swallow but a writer's job is merely to write a book. If they manage to write it in such a way as to engage their readers, make them care for the characters, intrigue them with the details of another world, well and good. That may even go towards making it a good book. But we as readers need to learn to trust the writer to include all the salient facts, the whole interesting story, within the confines of the covers. If we want more we have two options - to read more deeply than first we did (and this is certainly an option open to many, many of the HP fans), or to use our own imaginations to create new stories for the characters and worlds we've feasted on (and again, this is a route taken by many HP fans).
It's interesting to me to note that all the attempted sequels to Pride and Prejudice are unutterable disasters. Admittedly here there's also an issue of style - Austen being notoriously hard to mimic well, and very easy to imitate badly. But I think one of the main reasons is that Elizabeth and Darcy's story is so clearly told by the end of the book. Any attempt to follow it looks like a clumsily manufactured fraud of a plot. This is also why, for me, most of the best and most interesting HP fics don't focus on the central characters, especially Harry. There are a myriad of minor characters whose stories may still be told, but Harry's is already there in black and white in JKR's words. So let's leave him where he belongs and let JKR enjoy the real world for a change.