"No kind of backbone?" You're joking, right? Listen to the Petite Symphonie Concertante, which I described above. It's built around a very conventional Concerto Grosso structure & is basically monothematic. I'd liken it to Bartok's Music for Strings, Percussion & Celesta.

& I bet my life that you haven't listened to his Mass for Double Choir which is actually based on early Christian music. Depite it's imprecise tonality, which I admit can be a major hurdle for some listeners, Martin's music (like Bartok's) exudes adherence to traditional forms & ideas. He wasn't an iconoclast, he was just updating & modernising the old approaches...