Disney's "Hercules" is coming to Central Park as a musical, and this is good news. "Hercules" is an underrated post-Ashman Disney movie. People in the know feel that it didn't quite get the reception it deserved. One thing I like about "Hercules" is how closely it follows the blueprint for the Great American Musical. A successful musical often starts with a tone-setting number, a toe-tapper that lets you know who the main people are, and what the setting is. Think of "Tradition," from "Fiddler," or "Little Shop of Horrors," from "Little Shop." "Hercules" gives us "The Gospel Truth." After this, you need an "I Want" moment--and "Hercules" has one of the best, "Go the Distance," where the title character vows to leave his hometown and discover his purpose for existing. A Broadway musical should have a conditional love song, where a main character swear...