Harry Potter and the Deathly Hallows – Part 2, where Harry finally destroys all the Horcruxes and defeats Lord Voldemort (Ralph Fiennes), ending a giant war in the wizarding world.
Harry Potter and the Deathly Hallows, which was split into two movies, sees The Order of Phoenix and the students of Hogwarts team up in one grand action against Voldemort and the Death Eaters. The saga is brought to an end, but not without big sacrifices, such as the deaths of the just-redeemed Severus Snape (Alan Rickman), Remus Lupin (David Thewlis), and Fred Weasley (James Phelps). While the Harry Potter movies stayed pretty loyal to the books, the last movie made some fairly big changes, including Crabbe disappearing entirely from The Deathly Hallows.
One such change was leaving out an important scene in the seventh book, where Harry parts ways with the Dursleys, and Dudley thanks Harry for saving his life. He wants Harry to come with his family to a safe location amidst the wizarding war, and Harry comments that he would be a waste of space in their home. Dudley says he wouldn't, and Harry is moved by his cousin's declaration. Although director David Yates did film a short version of this scene for the last movie, it was eventually cut out. Leaving the Dudley scene out of Harry Potter and the Deathly Hallows means that Dudley doesn't get a chance at redemption in the movies. This is a pretty big mistake, considering the Dursleys' story arcs led to nowhere in the films (while leaving Peeves out of the Harry Potter movies may not change the story fundamentally, removing the Dudley ending scene does), but a Dudley sequel could fix the ending.
A logical solution to fix this mistake would be a Harry Potter sequel focused on Dudley and his daughter, who receives a letter invitation to Hogwarts. This story can explore Dudley’s gradual coming to with having a witch in his family, as his Muggle past with the Dursleys comes in conflict with his more recent experiences with the Dementors and Harry saving his life. His daughter’s relationship with the Hogwarts students would also be a rich ground to explore, as the students know about her prejudiced parents and may struggle with accepting her into her house. And most certainly, this situation would bring Dudley and Harry close together after two decades, a relationship which, one way or another, would lead to Dudley finally redeeming himself on screen.
While the sequel Harry Potter And The Cursed Child was a great success on the stages of London and New York, turning it into a movie would pose a serious casting issue (as Severus Snape is a key character in the story through time travel). In addition, talk about an HBO live-action Harry Potter series has left fans wondering what the show will focus on and whether it will include the original cast (Daniel Radcliffe, Emma Watson, and Rupert Grint). Although a story focusing on Dudley's family might not be able to generate a whole series, it would definitely make a good (and necessary) Harry Potter sequel movie.
