First off, comparing this album to Miles is absurd; it would be like comparing Monet to Fleming; both geniuses, but 2 different time frames, eras, periods and concepts.
Black Codes is pure modern jazz energy at its most urban, refined, freshest, sophisticated and complex; it IS a seminal album because it provides the natural evolution and continuation of a hard bop movement that seemed to be floundering a bit in the late 70's, always seeming to have to fight the mediocre commercialism and superficialness that was plauging not only the music scene, but American culture then, and still today.
Dark, moody, hip, furious, dissonant, deep---very deep, ahhh, there simply aint' enough adjectives. But if words are meaningless, then how about one sustained goose bump of pure reverie and jazz joy when digging this album?
What is especially astounding are the virtuoso performances of an absolutely sick, monstrous rhythm section, and the horn and saxophone blowing which is a reflection of the best of improvisational recording during the last fifty years. I agree with the reviewer: don't walk, run and get it. It belongs next to Miles, Clifford, Coltrane and Bird, but put this one last (or latest) in the line-up.