Bright colored pinwheels go 'round in my head.
It definitely is, in the sense that music is an artform. To my ears, I've loved all of the songs on Horizon and never noticed anything wrong with the pitch except for "(I'm Caught Between) Goodbye and I Love You" and "Love Me for What I Am." My perception of these tonal shifts on Horizon is nothing, though, compared to various tracks on A Kind of Hush ("You," "I Have You," maybe "Boat to Sail" and "One More Time") and On the Balcony of the Casa Rosada/Don't Cry for Me, Argentina on Passage, which I know were all sped up. To me, this messes with Karen's vibrato in a way that makes it sound not quite like Karen anymore.^^I understand what you are describing, however, unless my hearing is faulty,
there is nothing wrong with the speed of the songs on the album as originally delivered.
The "minor, but noticeable tape speed error" which you believe to be on the original album,
does not exist (as far as my ears are concerned).
I am asking why you believe that to be so (noticeable tape speed error) ?
You wrote "I'm wondering if that's one reason why they sped up the album."
My ears have never perceived the album to be "sped up."
I'm perfectly alright with your belief, but is this not subjective ?
Just my two cents. If anyone has a keyboard, try to play along with some of these songs and see if you can get an exact hit. Would love to hear others' feedback.