This is definitively the KC that I like the least. I find a lot of interesting passages, but not much that really grabs me. Even more, I find the sound in general and Belew's, in particular, a bit "annoying". I am not saying it is bad quality, it is definitely a set of creative choices that push me back, like constant high-pitched guitar and long vocal notes in a register I am not fond of. But I reckon it is a very good album, just not my cup of tea. I may compile an "alternate version" of the album that I could love, by finding later live versions of the songs.
I actually believe that the 5.1 mix is great and fits the music very well, and I like that there are different mixing styles for the main voice. I must admit that since I never listened to it in much detail, I can not compare the new mix with the original one, and I paid more attention to it now only because there is a surround mix available.
All in all, I think this album does have an important place in the discography and the 40 anniversary version is a great presentation. The full version of Requiem is a surprising improvement and Absent Lovers is a nice addition. A flawless presentation. Trying to be objective in my subjectivity, I gave it an 8.5 rounded to 9.