I'm from Seattle, and have been watching MM for most of his dance-making life. While I think he's certainly matured over that time, some of the fundamental elements in his work remain the same -- he has always had a very clear understanding of music and a sophisticated ability to work with it structurally. At the beginning, he set a lot of work to popular music (his work to the Louvin Brothers and to Yoko Ono were brilliant in the simplicity and clarity of working with lyrics/text) and often included some snarky and juvenile humor. People do compare him to Balanchine, in part because of the musicality, and also because of the integrity of the construction, but that doesn't always fit -- Morris' early dance training included a lot of ballet, but I think his experience as a folk dancer and as a student of Spanish and Flamenco was integral to his development. Balanchine's home base is always classical ballet, while Morris has a broader standing vocabulary. He will often choose very simple material (walking, skipping, galloping) that reinforces the rhythmic pattern of the score, where Balanchine or another choreographer whose primary responses are drawn from ballet will choose something from that tradition. But they do have this in common -- if you don't like the music they've chosen, you will not have a very good time in the theater.
I haven't seen his Orfeo, and so cannot comment on it, but have you seen his Gloria, or L'Allegro, or Mozart Dances? They all include examples of what you might think of as pedestrian movement, but for me, that creates a connection to the viewer that is powerful and direct. My kinesthetic response to the work is profound in these works.