When the Louisville Orchestra announced that Jorge Mester would be its next music director, many in the industry wondered what the ensemble’s leaders were thinking of. Mester, 71, served as Louisville’s music director for 12 years in the 1960s and ’70s, and is hardly considered a rising star in the conducting world. Furthermore, Louisville was rumored to have several top young conductors on its shortlist. So what happened? Andrew Adler says that, on reflection, Mester’s second act could turn out to be exactly what the financially strapped and frequently chaotic orchestra needs.