The Rock is the greatest wrestler of all time. Greater than Flair, Hogan, Sting.
He hasn't been in the business as long as those mentioned but in the short amount of time he was in it, he equalized or surpassed their levels imho.
The way he controls a crowd is unrivaled by anyone to date to hold a microphone in professional wrestling.
He's far from the most technical wrestler ( ala Bret Hart, Dynamite Kid, etc ) of course but when you sum up every aspect he surpasses everyone. He is a once in a lifetime kind of person; very eloquent in interviews; never stuttering while providing intelligent responses and clowning people in creative ways like you've never seen in promos.