What is your defintion of "hit" and "success"?
This is a serious question, because you may or may not be referring to critical acclaim and financial success.
There is nothing I've heard or read about this show that would lead me to conclude that it will be anything other than a hit, if measured by such things as reviews and awards. I would say that I'd be shocked if it did not win the Tony for best revival of a musical.
On the other hand, I have no idea how the show will do long term at the box office. Will it recoup, and go on to be profitable? Who knows? What does everyone think?
Cinderella might turn out to be more of a financial success, but I have no idea about that either.
CZJ at opening night party for A Little Night Music, Dec 13, 2009.