1 Duran 2 Leonard 3 Pacquiao 4 Hagler 5 Hearns 6 Marquez 7 Morales 8 Barrera Marquez, Barrera and Morales are pretty interchangeable, and you might rank all of them over Hearns. Some will put Leonard over Duran, and that's fine I think. If Pac beats Mayweather that will raise his stock, not sure if he could rank over Duran and Leonard though, since he is still active its hard to review his carreer.
Well I don't think you can present even a passing argument that Morales, Marquez or Barrera should be ranked above Hagler or Hearns. Only Pac can reasonably be ranked above any of these guys. So "bias against Pacquiao" is a much better question. I think he will rate among those guys if he beats Mayweather. If not, he doesn't.