The Ildjarn works I mostly come back to are Ildjarn-Niddhog, Hardangervidda, Sort Vokter, Strength & Anger, Det Frysende Nordariket, Forest Poetry, Landscapes... Wait a minute...
If you're complaining that Ildjarn isn't musical enough than I think you're missing the point. Except for the ambient works, I don't think it "expresses" anything that one can put into words. It exudes the primitive, primordial, basic, simple; and it does it in a way that is convincing and hypnotic. If you sit there and over analyze his music, or try to find something meaningful in individual songs or riffs, you probably won't. Let yourself experience it.