Robert Spano finally makes his New York Philharmonic debut. The Philharmonic has been “catching up with the younger generation of American conductors lately, perhaps with too great a sense of dutiful deliberation, and Mr. Spano’s debut lets it check off another name on its list. But there is also a sense that the orchestra is scouting out talent for its eventual search for its next music director — a process that would have to involve establishing relationships with the potential candidates. Mr. Spano’s name, along with David Robertson’s and Alan Gilbert’s, has been mentioned as a possibility, although mostly in the context of critics’ wish lists, not by the orchestra itself.”