I'm belatedly replying to this topic because I was away and only then discovered that Audiogon won't allow you to log in from another country.
Anyway, @lordmelton, I'm not sure what you mean by the assertion that the earlier Steely Dan albums showed a sequential "improvement" one over the other.
Harmonically, Steely Dan's music became progressively more complex over time and moved from the harmonic vocabulary of rock and country towards and into that of jazz, notably from Aja onwards and through the remainder of the Steely Dan record releases. [That's with due acknowledgement to the fact that there are elements of jazz and rock vocabulary on nearly all of the albums].
As someone who is genre agnostic, I personally love all the albums, but comparing something like, say, My Old School to, say, Babylon Sisters is just impossible - apples to turnips etc,

