From what I've heard, I don't think he ever beat the studio vocals to any of his songs on stage. He gave many great performances, with great vocals, but for me, nothing that actually surpassed the studio masters where he is locked in and focused on giving the perfect vocal take. Not to mention the hours of vocal exercises prior to recording. Sure, I love Human Nature live, but do I think he ever surpassed the studio master vocally on stage? Not really.
The only song that really comes to mind as maybe being better performed on stage is "Who's Lovin' You".
hmm...I kinda see what you mean. When I posted, I was thinking in terms of 'performance' not just vocal. I misread I guess. So yes, I actually do agree with you