Giants limped into the playoffs with seven losses, barely making it via a win in the last game against Dallas to take the crown for an awful division. Like you said they got hot at the right time and there was a lot of luck involved. Not just in the SB but the NFCC.
That year's D for the Ravens allowed lots of yards but they were great in the red zone. Being eleventh in rushing is a hell of a lot better than 22nd.
Pats, 13th in D is nothing to sneeze at and they have a HoF QB one of the best of all time so that sort of counterbalances a run game.
Pack have Rodgers, Saints D that year was good with turnovers which makes up for some things, plus that's the NFC. Sure there's outliers but generally in the AFC you needsomethingmore than the one dimensional teams the Colts have been fielding with Luck.