I don't believe blinding speed and scoring tries are the only traits in determining a great winger. Other factors such as defense, reading of the play and positional play are very important also. Very few wingers have a 'good football brain' and it's these ones which become the great ones.
Hazem, Luke Burt and Sing are a few that spring to mind that have these qualities. And Matt Sing simply had it all. Watch him score tries, watch him blitz the defenders, watch him backing up his team-mates for the final pass and watch him make amazing defensive efforts (including if I recall correctly about four held-up tackles in an Origin match circa 95). He was the complete package and did it over a lengthy period at various levels of the game.
There certainly won't be any youtube videos of Offiah making tragic defensive errors or stupid mistakes. Not to denigrate the man as he was most certainly a memorable player in our games history.