Fred Astaire himself was impressed with Michael, and Astaire was known for never complimenting other male dancers.
To say he's just okay is, to be frank, absurd. Technically he is superb, despite lacking even the most basic training. His lines are perfect, he has incredible grace and ease to his movement, he has incredible speed, and he connects each step seamlessly, flowing together beautifully.
He looks effortless when he moves. His ability to learn and pick up steps as quickly as he does is a testament to his natural, innate understanding and ability in dance. Other dancers have said they've never seen anybody pick up moves as quickly as Michael; these are trained, professional dancers who make their living off of that discipline alone.
Nobody in the pop world is anywhere near Michael. Michael's like a professional. He routinely makes professional's look average, and that all comes down to his natural ability. They may have far more training and practice then he does and are able to do physical feats which he cannot, but their initial movement isn't anywhere near as good.
What makes Michael truly extraordinary is his combination of blazing speed and ability to, at the same time, keep each movement as clean, as sharp, and as clear as can be, with his perfect symmetry, amazing balance, control and coordination. He can come out of a slick as oil step, going blindingly fast, and then just stop on a dime, freeze, and go in a totally different direction, all without ever giving up excess movement or appearing sloppy.
He's the total package.