I got one comment, from my buddy Myrhaf, which deserves a full response:
"But seriously, I'm sure your statistical analysis is sound. However, I wonder how you measure intangibles, such as will to win, work ethic, intelligence, etc. Do those traits show up in statistics? What if a great quarterback is on a bad team? And what about charisma, fame and overall impact on the game, as in the case of Joe Namath, who became a cultural icon? Should that be a factored in? Broadway Joe probably got more women to watch football on Sunday than anyone else in history. Isn't that important? Is there a difference between importance to the game and greatness as a quarterback?"
A great quarterback's intangibles will show up statistically IF the rest of his team is good enough. Football is a team sport. Unlike golf or tennis, greatness at any football position has to be viewed within the context of the team. Objectively viewing quarterbacking greatness can only be accomplished through statistics, including but not limited to championships. It is there that we view the meeting of ability with opportunity.
Consider "will to win". No matter how much a quarterback wants to win, he cannot do it if his receivers drop his passes, the running back fumbles a lot, and his team's defense is a sieve. On the other hand, a quarterback who is surrounded by a great team, but is otherwise not very capable, may not win despite his desire.
How about "work ethic"? Ask Billy Volek how important work ethic is. He went from being named the Titans starting quarterback in the preseason, to being demoted to second string, to being traded in the same year. From what I hear, it was all because he took the starting job for granted. In the modern era, quarterbacks HAVE to have a good work ethic. We could say Peyton Manning has a better work ethic than Tom Brady, but does that mean Brady is a slacker? No.
"Intelligence" is one of the odder intangibles. Clearly a certain amount of intelligence is required to even be able to play quarterback in the NFL. Beyond that, what does greater intelligence gain a quarterback? Consider the following two Wonderlic scores (which measures intelligence): Dan Marino - 16, Ryan Leaf - 27. Or how about Terry Bradshaw vs. Roger Staubach? I think Staubach would have given up a few brain cells to have won the two Super Bowls he lost to Bradshaw.
The "great quarterback/bad team" (otherwise known as "The Archie Manning Dilemna") is the hardest part to quantify. How much does a bad team detract from a great quarterback's statistics?
Imagine if you were the world's best accountant, but you were working for the world's worst company. While your work would be perfect, you would continue to receive no recognition, all because the company was awful. But you stay there year after year, doing perfect work, but accomplishing little in your career. Whose fault is that?
At some point, a quarterback has to realize a team will not help him win. Sometimes, your decision about where to work can be every bit as important as how well you work. In Manning's defense, the free agency rules of the 70's made it a lot tougher to change teams. But Manning never tried until he was already past his prime.
"Charisma, fame, and overall impact on the game". This is the style-over-substance factor. But this also comes into direct conflict with the "great quarterback/bad team" factor. Joe Namath clearly had more charisma, fame, and overall impact on the game than Archie Manning. Ironically, they both played 13 seasons, with almost the same number of pass attempts (Manning had 3,642, while Namath had 3,762). Statistically, theie career numbers are very close (Manning's numbers are first):
Completion percentage: 55.2% vs. 50.1%
Average gain per attempt: 6.57 vs. 7.35
Touchdown percentage: 3.4% vs. 4.6%
Interception percentage: 4.75% vs. 5.85%
Super Bowl championships: 0 vs. 1
Average rush yards per carry: 5.7 vs. 2.0
Passer rating: 67.1 vs. 65.5
At the very least, the statistics prove that Manning belongs in the same class as Namath.
But what about that Super Bowl? The "guaranty"? The first AFL victory over the NFL in a championship game? Namath's importance in the history of the NFL is unquestionable. But by any objective measure, he cannot be named the best quarterback in NFL history. He was immobile and threw too many interceptions. By today's NFL standards, he would be lucky to make a team. Don't believe me? Consider Ryan Leaf, who is considered a failure by modern standards. Leaf's career interception percentage of 5.5% is better than Namath's.
Looking back at Namath's career, the Jets won IN SPITE OF Namath, NOT BECAUSE OF Namath. Even if you look at that one Super Bowl, what did Namath do? Heck, running back Matt Snell, with 30 carries for 121 yards and the Jets only touchdown, deserves more credit for the win than Joe Namath does. All Namath did was NOT throw an interception.
While Namath has become part of football folklore, I would actually give the Chiefs credit for sealing the AFL legitimacy argument. Their victory over the Vikings in Super Bowl IV gave the AFL two wins out of the first four Super Bowls.
Namath is proof that importance to the game and greatness as a quarterback are two very different things. Namath is proof that historical importance is subjective.