After years of 'slow' progress, the release was rushed in the end, and the result is more of a compilation of the Invincible sessions, which all in all were more about exploration and authenticity for Michael, than appealing to an audience or about overall 'aural integrity'...
It could have become several different albums (it later did, in a way) but was probably prevented from that back then by the corporations.
The sessions had so much interesting music that the concept of *Invincible* is bigger than the album itself. We have yet to see the full scope of it…
Unpopular opinion mayhap, but it's my take