New York City Ballet is, like every other dance company on Earth, marking George Balanchine’s centenary with a series of special performances highlighting the master’s work. Unfortunately, says Robert Gottlieb, City Ballet chose to cast a decidedly washed-up ballerina in two of Balanchine’s most beloved roles, and to allow “echt Broadway” star Susan Stroman to stumble through “a two-and-a-half-hour piece with barely a step in it beyond the most rudimentary. There’s so little dance content, you can hardly even call it pastiche; it’s a show, it’s a hit, but it’s not a ballet.”