I have enjoyed the books and films from the start. The books progressed into something darker and more mature over the years, as did the characters and the actors who portrayed them. The films stayed essentially true to Rowling's vision and will last because of it. I enjoyed the final film as much as any of them, although it did not convey the same amount of suffering and grief to me as the books did. Maybe that would have been impossible. Another criticism, which is likely to be made of the film, is that the plot only really works for those who know the whole story. That did not bother me at all - and neither will it trouble most viewers, who have been following it from the start.
The actors will now be able to get on with the rest of their lives. As for Rowling, who knows. She will never create a world as complete as that again, but she may well go on to spin a few more entertaining stories yet. I bet they won't have spells and magicians in them though!