I'm glad to see this thread revived. Much of it focuses on ALW and some of his "sung-through" musicals. I haven't watched my Blu-Ray of "Love Never Dies" lately, in part because I'm thinking about writing a phan-phic novel of "The Phantom of the Opera," as if there weren't enough of them already, and I don't want my sequel segment influenced by LND. Nonetheless, if I recall correctly, LND has a significant amount of dialogue.
Are a few lines of dialogue, in other people's views, enough to eliminate a musical from being considered "sung through?" If so, POTO is not actually sung through: there's a dialogue exchange when Raoul and Christine reconnect in her dressing room after her debut performance; the Phantom asks, "Did I not instruct that Box 5 is to be kept empty for my use?"; Carlotta tells Christine, "Your part is silent little toad," and the Phantom answers her; the Phantom says, "She is singing to bring down the chandelier;" and, before the performance of the Phantom's opera, Raoul, the managers, the police officers, and the Phantom discuss whether and when to shoot. I can think of several other pieces of dialogue, as well. Nevertheless, the show is, of course, primarily sung.
Audrey, the Phantom Phanatic, who nonetheless would rather be Jean Valjean, who knew how to make lemonade out of lemons.