Many people look at musicals as entertainment or escapism and not "serious" but I think they overlook the themes and lessons that are contained in the musicals, either explicitly or implicitly. The lessons may be subtle but they can be found.
Musicals I never tire of are Singing in the Rain, Caberet, Seven Brides for Seven Brothers (because I remember how one of my brothers and I would vigorously dance to it), The Producers, and Bye Bye Birdie. If I can catch it on stage, I will not miss seeing Pippin.