Broadway is booming, but what’s happened to the grand old tradition of theatrical dance? “From the galumphing knights in Spamalot, to the interminable Old Navy commercial that was Good Vibrations, to the ballroom gliding in Dirty Rotten Scoundrels that brought to mind the Geritol-flavored heyday of Lawrence Welk, the choreography in musicals this season often seems intended not to capture your attention, not to illustrate the breathtaking possibilities of the human body in motion, not to make a case for dance as an indispensable ingredient in musical theater.”