“This Ain’t No Disco”, an original rock opera about the art, music, and dance club scenes of 1979 New York, ain’t kidding.  This new musical is bland and soulless, overstuffed, overdone, and under-dramatized, with a cacophony of characters, ideas, and issues offering only a sprawling, shallow story that is neither unique, distinctly tethered to the history of the setting, or frankly, engaging.  This isn’t just a flop, but a belly flop—the likes of which you rarely see on stage in New York anymore.