Well there was a couple of different versions that were floating around which I think showed a major problem with the show (which I by the way loved) - in that it wasn't "finished" - it was still a work in progress.
In London, there was a ghostly reprise of the "Trio" from the end of Act 1 with Marian singing to the tune "Evermore without you" - "Go to Laura now..."
and then I think it ended with Marian alone singing I've got a secret
The Broadway version, which I saw twice changed and the last time I saw it, Marian sang a reprise of "Evermore without you" once Walter and Laura were offstage and then the Lammastide wedding scene concluded it (which I really hated...)
Funny thing - ALW has totally soured on Woman in White. Read his interview on the Whistle Down the Wind Tour site (you have to scroll down)
http://www.thewhistletour.com/news.htm the part I'm referring to:
The Woman in White was the one expected to be your "next Phantom," because it was a romantic thriller with a lush score. But the Broadway run lasted only three months. Was the high-tech production (using projections rather than "real" scenery) right for the show? Was the plot too convoluted?
A: I will say that I felt the first act was as good as anything I've done. But two-thirds of the way through the second act, the story disintegrated and there's no show.
I realized, perhaps too late, that tale is difficult to tell today, because it all revolves around a secret. And in today's world, there's no such thing as a secret. You never know until you've written it and put it on stage. You roll the dice.
It's always a combination of factors. Who knows, if we'd exchanged directors on Cats and Phantom (meaning Trevor Nunn doing Phantom and Hal Prince doing Cats), those shows might have worked out differently.