For years New York’s Mostly Mozart festival was a listless affair that many critics thought should be put out of its misery. But under the festival’s new music director French conductor Louis Langrée, the enterprise has been reborn. “Though Mr. Langrée can be credited with the rejuvenation, he has had a crucial ally in Jane S. Moss, the vice president for programming at Lincoln Center. Back in the dreary days when Gerard Schwarz was the festival’s music director, the playing of the orchestra was listless and, even worse, pointless. The musicians would run through a performance of a staple like Mozart’s Symphony in G minor, and you’d wonder why they were bothering.”