It is foolish, of course, to try to judge a music director’s tenure with an orchestra after only six months, but the immediate effects of a new arrival on both ensemble and audience can have a significant impact on the evolution of the relationship between maestro and musicians. In Boston, where James Levine is now firmly ensconced as music director, observers have begun to notice a distinct shift in how the orchestra is perceived. More young people have been showing up at concerts, and a number of musical heavyweights who couldn’t be bothered with the waning years of the Ozawa era are back in the fold as well. “Clearly, Levine’s programs are sparking all this interest. They are long; they are challenging. He is striving to create concerts that are at once provocative to the musically trained, yet not off-putting to the more casual concertgoer.”