Unfortunately, DVOA, the Football Outsiders' wunderstat, seems to paint the Saints as a mediocre team.
The unfortunate part isn't the stat itself, the unfortunate part is that the stat is dead-accurate.
According to the Football Outsiders, the Saints are 21st in the league in team DVOA, - 12.4%. Their offense is a bit disappointing, 11th at 8.7%; their defense is a horrendous 29th, 16.6% (remember that positive defensive DVOA is bad). Most disappointing, their special-teams DVOA is 28th, at -4.6%.