Ross and Curry had better records their last 2 years than their first two years. Both walked into a mess, although for different reasons. They both left things better than they found them.
Johnson's record his last 2 years was worse--by far--than his first 2 years. You can't say he left things better than he found them.
I could debate this all night, but the bottom line is that looking at his whole body of work, Johnson was a mediocre head coach.
53-53 FBS over the last 9 years. There is nothing else to debate.