Peter Gelb has big changes in mind for the Metropolitan Opera, and the opera world is interested. “He said he would emphasize directors with theater and film backgrounds, embrace digital delivery of opera, bring in conductors like Riccardo Muti who have never conducted at the Met before and introduce major voices in new roles, like Karita Mattila as Tosca. Mr. Gelb will also establish a joint commissioning program with the Lincoln Center Theater, which would solicit works from musical theater composers as well as from more traditional classical composers. He will increase the number of new productions from about four a season to seven.”