There were only four Super Bowl-winning defenses in 49 years that did not rank in the top 12 in points allowed during the regular season.
And none of those four would have won the SB without outstanding defensive performances in the playoffs. They all had playoff games in which they held the opposing QB to 30 points below his season rating, and they all held the opponent under 20 points per playoff game on average. Based on that last stat, these four defense's level of play in the playoffs was the equivalent of a top 12 defense anyway.
a good defense is important , and really they just have to play great during the playoffs and SB.
But a team also has to have a pretty good offense too. other wise they can still lose if they cant score enough points.
What I see is
teams that go to SB are the teams that get hot and can stay hot.
Players have to step up and make great plays, like the NE DB who intercepted the pass at end of last years SB.
Catching a pass on your helmet etc.
One thing for sure you are not usually going to get to SB with a weak defense, Denver did and Seattle then blew them out.
There is no 3 players that can make a team good enough for a SB run, it takes a whole team , including the coaches.
Even then like seattle last year, do everything right, and it comes down to one play or moment and if you screw that up,
you go home a loser.