Mussina was very good, but he was never dominant. His three best non-asterisked contemporaries are Greg Maddux, Randy Johnson and Pedro Martinez. Mussina had two seasons with an ERA+ above 150 (1992, 1994). His highest was 163. Maddux has nine seasons over 150 with a high of 271. Randy Johnson has eight such seasons with a high of 197. Pedro Martinez has seven of them (five over 200) with a high of 291. They all had consistent peak runs better than Mussina’s best individual season.
Those three are the great pitchers of his generation. Mussina’s not as good. He’s not even in the discussion.
Strict constructionist that I am, I can’t consider Mike Mussina Hall of Fame material. Though, he won that meaningless late September start against the Red Sox to get 20 wins. In the inclusive and misguided system in place, that probably seals Mussina’s entry.