Surprised to read they're actually talking about casting leads for this. A few years ago, we enjoyed a great night at the Bowl when they screened a new restoration of the 1962 film, with the ORCHESTRAL score played live by the LA Phil (I think). They artfully managed to meld the soundtrack's singing voices with that live orchestra-- really the best of both worlds, we thought.
I myself find park-and-bark concerts the least good format for appreciating great shows like WWS.