my humble opinion
In my humble opinion, the ride closed down because it was possible for someone to throw or spit off of the ride and hit people down below. Liability becomes an issue in such circumstances, and people just LOVE to sue Disney for any imaginable reason. Another theory I have is that, from the ride, it was possible to see the backstage areas. It is rare that when you are "onstage", that you can see a backstage area, so I think Disney wanted to keep that constant and eliminate the skyway. These reasons are merely speculations on my part.