Yea, I understand that those extraneous tracks aren't songs you'd probably listen to everyday, but those tracks really do add to the beauty of the album as a whole. Especially in Come on Feel the Illinoise, those "filler" tracks (instrumental) are too vivid and involving in themselves to be called filler. If you actually sit down and do nothing else but listen to the album as a whole, you can really sense a purpose in those arrangements and track placements as they tell their own stories and transition from one piece to the next.

Also, Sufjan doesn't really have that many albums. Maybe you meant songs, which I'd have to agree, he does have an epic number of.