It’s looking more and more unlikely that New York City Opera will find a home in the performing arts center planned for the World Trade Center site. Space for the center has been reduced by 20 percent. “Given the reduction in the space available and the footprint that City Opera says it needs, it would seem that a significant change in plans would be needed to accommodate an opera house. The opera has proposed a new house with a 60,000-square-foot footprint, Paul Kellogg, general and artistic director of the opera, said in an interview yesterday — so 40,000 square feet would appear to be severely inadequate.”