I think it would be hard to compress all that material into one 2 1/2 - 3 hour musical. Unless they were to do a musical of each book, which I doubt would happen.
On the other hand, part of me wonders how it would be if it actually did get pulled off. For intance, it would be interesting to see how (or for that matter, if at all) a director would portray Quidditch on stage. The show would definatly be a spectacle. I think there would definatly have to be top - notch creative team, including an excellent book writer and director, in order to attempt a Harry Potter musical.
I seriously doubt it would happen, but I guess you never know. Two years ago, I wouldn't have thought a Lord of The Rings musical was possible.
"You drank a charm to kill John Proctor's wife! You drank a charm to kill Goody Proctor!" - Betty Parris to Abigail Williams in Arthur Miller's The Crucible