John Hollinger does this annually. Blake Griffin is ranked 2nd this year behind Ty Lawson, who scored surprisingly high. Overall, Griffin is the 6th highest rated prospect since 2002, behind Dwayne Wade, Carmelo Anthony, Kevin Durant, Mike Conley, & Lawson. Many of the rankings, both past and present, are suspect.
Hollinger offers a semi mea culpa on Eric Gordon's low rating last year: "Gordon is perhaps easier to understand because he was playing hurt at Indiana and his primary skill (shooting) didn't show through statistically, but that doesn't excuse the others."