You can examine how SEA has completed its circle of life with its 2013 campaign, covering all possible combinations of good&bad offense&defense. See how DEN's offensive production changed with the arrival of Peyton Manning (or check out IND's 2011 year in the wilderness).
The reigning champions are always the default selections for all our charts and tables at ANS, so this is will be the last week as the default for my hometown team. To me it's interesting to see that they've spent most of their franchise's existence along one axis, ranging from all-world defense/terrible offense to above-average offense/average defense, and won the Lombardi Trophy on both extremes of the axis.
It's rare for a team to sustain above-average production on both sides of the ball for beyond a season or two at a time, even for perennial contenders like NE and IND. PIT might be the best counter-example, with seasons that cluster in the upper-right quadrant consistently through the recent era. Even their "down" years were decent. For example, 2013 saw the Steelers finish 8-8, falling perfectly at the average/average intersection in the plot.
CHI's plot is a really interesting one. They should feature it on Sesame Street. One of these years is not like the other...
It's interesting to see how the average line can appear to be something like the sound barrier to some squads. ATL just can't seem to put together an above average defense, and BUF can barely break the average-barrier on offense.
A smaller version is included below, but the permanent full-size version is available via the Tools | Visualizations menu.
As always, up and to the right is good. Down and to the left is bad. My thanks to Chase Stuart who suggested the idea for this a couple years ago.