The 1972 Miami Dolphins plays divisional opponents with a .360 combined record. The 2007 Patriots’ divisional opponents had a .240 combined record. Since they played each divisional opponent twice, this seems significant.
While you've already apple/oranged, in comparing general opponents to a subset, it is significant in a different way. Aside from the Giants, who didn't play another regular season game after playing the Patriots, only one opponent of the Patriots beat a team that wasn't the Jets or Dolphins the week after playing the Patriots, and several lost at least the next TWO games. The only team that one could say played well the week after was the Browns beating the Dolphins by 10.
The flip side of your comparison is that the Patriots beat the entire NFC East, including their champions and two Wild Card teams, and the champions of the AFC West, North (and the 10-6 Browns, who would have been the Wild-Card team if the Colts hadn't dogged their last game), and South, in the regular season - the Dolphins played no comparable games to any of those. The Patriots beat TWO teams which ended up 13-3, at times when they were undefeated.
And the Pats also have played and beaten 7 playoff teams (one of them twice) and now have to beat another one that they just played 5 weeks ago.
They beat who was there to be beaten.
What is really significant is that the 1972 Dolphins played two teams, in the regular season, with winning records. The Giants and Chiefs .... both finished the season with 8 wins and 6 losses.