Broadway's Frozen is a good show. With its music, its dance, its flurry of likable leads, and snowball after snowball of son and lumière, some of it newfangled, some of it stretching back to 19th-century melodrama, it offers most of the pleasures that we count on Broadway musicals to provide. But even with the addition of a dozen new songs by the composers Kristen Anderson-Lopez and Robert Lopez, an enhanced book by Jennifer Lee, and the interventions of director Michael Grandage and scenic and costume designer Christopher Oram, it rarely feels like more than the movie and sometimes it feels like less.