The darker elements of “The Great Gatsby” prove more elusive, which blunts the impact overall. So does the show’s anodyne Broadway sound, which is poppy and pleasant without being memorable. It summons neither the Jazz Age, like the soundtrack to Jack Clayton’s 1974 movie adaptation did, nor a spirit of wild abandon, like the soundtrack to Baz Luhrmann’s 2013 take. The score to this “Great Gatsby” is missing a vital urgency.