I should have seen this one coming .... I dunno - to me it is just (very) good improvised music for solo instrument.
When I am in the mood to listen to "Jazz" I would never play the Koln Concert. My Koln Concert mood is more similar to say Indian raga (hariprasad chaurasia) or say Anouar Brahem). Not sure what label to stick on it.
I just picked this album up yesterday and completely agree with this post.