Last summer, in a rave-reviewed show, Rufus Wainwright channeled Judy Garland at Carnegie Hall, and now he’s writing an opera. His ambitions, it seems, are increasingly outsize, and on Release the Stars, his fifth studio album, it feels like a mere pop album can’t contain him. Alas, adorned with more strings, horns, choirs, and piccolo flute (!) than ever, his melodies — and what melodies they are — are drowned out by the bombast (see: the syrupy ”Nobody’s Off the Hook”). But he still yearns more beautifully than anyone.