Francesco Zambello is an acclaimed director who has worked in the world’s top opera houses. So why is she working for Disney, creating a show for their theme parks? “I’m a populist, an opera evangelist. I believe in making shows that speak to a broad audience. I’m not afraid of the word `entertainment.’ So far the sort of mainstream hit scored by other ‘serious’ directors of opera and drama like Trevor Nunn (with “Cats”), Nicholas Hytner (“Miss Saigon”) and Julie Taymor (“The Lion King”) has eluded Ms. Zambello, and not for lack of trying.”