Let’s keep it simple player (in college) only.
If we're talking simply on field performance only:
Ernie Davis (Heisman, 2 time AA, NC, COF HOF, #1 Overall NFL Draft Pick)
Jim Brown (Multi Sport AA, COF HOF, #6 Overall NFL Draft Pick, NFL HOF, Arguably greatest player to play at the NCAA or NFL levels)
Floyd Little (3 time AA, COF HOF, #6 Overall NFL Draft Pick, NFL HOF, Gained the most yards of the 3 at the college level)
Then there is a big gap here...
Michael Owens (1k back his senior year, 2k career yards, 9th round NFL pick)
Rob Konrad (over 1.5k yards during career, 2nd NFL round pick)
Terry Richardson (9th round pick, over 1.5k yards during career, Undrafted)
Then I think you have a group of:
Tom Stephens
William Schoonover
Glenn Moore
Richard Panczyszyn
And then Mandel Robinson.
I don't really consider anyone before Jim Brown part of the discussion. And I gave Ernie the nod because he won the Heisman (I know JB got robbed).
And there are a number of former SU backs that would be above the second group if they wore the 44, starting with Larry Csonka and Joe Morris. But guys like Walter Reyes, Sean Tucker, Delone Carter, James Mungro, David Walker, Dee Brown, Jerome Smith etc.