It really is hard to say because he just kept raising the bar from when he first stepped on stage. The man was a force of nature when it came to music and dancing. The complete package who seemed to be put on this planet to generate classics.
Young MJ belted with saturated emotion like he was an old man who'd been through the mill and had his heart broken a million times before being reincarnated as a kid who still remembered how it felt.
The Jacksons era had him experimenting after dealing with puberty's shift and its when he started developing his steps beyond his James Brown renditions as well as songwriting.
OTW and Thriller speak for themselves as they tell you of a man on a mission to obliterate the limits placed around the neck of Black artist in an world that would give them no spins due to the color of their skin because his talent forced the world to pay attention.
Bad to Dangerous introduced an edge and grit as well as the seeds of what what would sprout into his paranoid glimpses behind the curtain of reality and it was in this era his vocal tones shifted to solo shot leads to lush multitakes of layers in perfect pitch as well as his own production.
HIStory was back against the wall, let em have it with two barrels smoking, hit em up "Oh you thought I was dead?" as he just emptied the clip on his enemies who thought he was just going to take it without reacting and that was some of his best songwriting, social commentary and production with him handling most of it, dolo.
Invincible was decent but bloated and too late because he was high as a kite for most of the sessions, riding trends instead of setting them and tired after a life of fighting for a shred of sanity after having been raped in the press, again and again. Even that was calculated because there was some heat laid down in those sessions but he wanted to keep that for his next venture for when he got off Sony so there was a method to the madness before they hemmed him in and murdered him then got away with it.
How can you pick a peak/prime when
the nearest comparator to your level of global fame and influence was the prophet of a religion with billions of adherents? Let that sink in and consider the implications when you consider the life of the once and future King. And before you think I'm blaspheming or hyping MJ out of scale consider this:
That alone speaks volumes and illustrates well what I've said. If you witnessed his presence in this flesh you know what it is...
Stevie from 68-85
Michael Jackson has more talent in the hair on his balls than Stevie Wonder.