I think the world of Harry Potter would make a great RPG. Ideally, they would set it well before Harry's birth, or even before the first war. Perhaps before even the rise of Grindlewald. The world's certainly rich enough for a good game to be made out of it. For selfish reasons, I'd hope to see something more like KOTOR than LOTRO, just because I dislike paying monthly subscription fees, among other things. But that's a different topic.
KOTOR showed us you can have a wonderful game based on a licensed franchise. So it's definitely possible for a great HP game to be made. And KOTOR set it well before the movies, allowing for unique characters and its own storyline.