What I'd love to see is an adaptation of the stage version, which debuted in Germany but never had a Broadway run in its English translation. (I saw it last year at a local community theater, and the production was great.) This is much closer to the original book (sadder ending and all), with some elements from the original movie, and extra songs (including at least one that was going to be in the original but was cut). They also added some wrinkles of their own...this version restored Jehan, Claude Frollo's feckless brother, but made Quasimodo his son by a gypsy woman. Jehan's gypsy wife died in childbirth and Jehan was stricken with the plague, charging Claude with his nephew's care on his deathbead. There was some extra depth to Frollo's character...he blamed the gypsies for leading his brother astray, which fueled his hatred for them, but it was his own decision (Claude's back to being the archdeacon here) to spare Quasi. He masks his desire for Esmeralda in a desire to "save her soul". And in this Disney stage musical...there's a brothel and an attempted rape. Much more adult and complex than most of Disney's stage shows, even for an adaptation of an animated movie that was more complex and adult than their usual fare.
Phoebus himself is given far more depth as well...he's just returned from the front lines of a war, and some of his lines in his introductory song "Rest and Recreation" indicate that his experiences have taken their toll on him. Unlike in the book, however, he genuinely loves Esmeralda and is not just using her.
And Quasi himself? His deafness is restored, and his speech patterns reflect that whenever he's talking to Frollo or anyone from the outside world. But when he speaks to his "friends", the statuary of the cathedral (there are gargoyles as well as statues of saints and such, and they're NOT played for wacky comedy), he speaks normally. Furthermore, this version does something I wish the movie had done...makes it clear that the statues are Quasi's "imaginary friends" and that their conversations happen only in Quasi's mind. Hence, the difference in speech patterns.
And if anything, the score's even better than in the movie version (which was, itself, one of the best Disney scores, and possibly the last of the really great Alan Menken Disney scores.)
So if they adapt this for live-action, they could do a lot worse than to adapt the stage version (especially since it didn't get a large-scale American production in the form of a Broadway run).
Have a look at the Paper Mill Playhouse production.