I think, if "Rebecca" ever opens on Broadway, it will have a decent shot. The novel has become a true English language classic. If the musical manages to reproduce the mood of the book (its brooding sense of doom), that would be quite an achievement -- one that should guarantee a hit.
Also, the fangirls and overgrown fangirls (like me) haven't had a new musical in which to squee at a male lead in some time -- POTO is a fave, but let's face it, most of us have seen it over and over. Dr. Zhivago was the most promising romantic musical in some time, but it apparently decided to make war and not love.
"Rebecca," however, is the stage equivalent of a "chick flick." Whoever is cast as Maxim de Winter will undoubtedly be a heartthrob, no less than Tam Mutu or James Barbour, both of whom were slated to play the role. With a sympathetic "I" and a properly malevolent and charismatic Mrs. Danvers, the dramatic potential is enormous.
I think the producers realized that they were seeking audiences who have spent a lot of time at the Majestic -- they cast a bunch of Phantom expats, in both the first and second casts. If James Barbour goes from mask to Maxim, he will be yet another Phantom alum. If the show can capture the women who can't get enough of POTO, it should do fine. It may not run for 27 years, but 5 would be a possibility.
Just my two cents ... or my wishful thinking.
Audrey, the Phantom Phanatic, who nonetheless would rather be Jean Valjean, who knew how to make lemonade out of lemons.