re: 1991 Washington Redskins is the best pro football team of all-time

Gibbs was great. He won three Super Bowls with three very different teams and three different styles and with thee different QBs, two of which could never and would never come close to the Hall of Fame.

I'm not sure how you can say this team or that team's schedule was objectively more or less difficult when comparing different years. There is simply no measure that could accurately determine that statement.