To judge by her interview with Charlie Rose, her approach to programming seems to be inspired by Michael Tilson Thomas: looking for novel ways to promote living composers, and selecting modern compositions intelligently (i.e. avoiding some of the annoying and vacant ivory tower stuff which gave modern music a bad name).
One thing, though... I've never heard a music director who supports modern music, such as Alsop or Thomas, articulate the most obvious benefit to cultivating an interest in living composers: that once you find one you like you can look forward to the next thing they create, and participate in the unique experience of listening live when that work is performed for the first time.
Here's something I'd LOVE: for a major symphony orchestra that gets a lot of premieres (ideally San Francisco) to by policy broadcast every world premiere on XMRadio or some other real-time mechanism, even if the rest of that evening's program cannot be simulcast. Then, the orchestra sets up an official internet chat room for folks to make real-time comments in as they all participate in the shared experience of hearing this work for the first time. That way you get not only the enjoyment of the premiere, but the camaraderie of folks all over the world who are also fans of that particular composer.