So far, it sounds like the ingredients for a massive hit. So far, the only indications I see that it may completely fail are either the Lord of the Rings syndrome (budget far too big to sustain the show) or a plot convoluted to the point of incomprehension.
Bono + Taymor + Beloved superhero + massive spectacle
And it has been explained time and again that it will not be a standard book musical, so I'm not sure where people get the idea that it will be lame, laughable, or bad. Other than the theatre elite, of course, who cannot tolerate popular entertainment on Broadway.
"What can you expect from a bunch of seitan worshippers?" - Reginald Tresilian