Agree to disagree, but the Seahawks are case and point of what I am saying. If you build a team around a dominant defensive secondary, you stand a better chance against top NFL offenses than teams that build dominant d lines.
The Niners and Broncos not only had much better offenses than the Seahawks last year, but they had better defensive lines as well. The difference in those games? Defensive Secondary.
Lots of teams had better D lines than the Seahawks did last year, but no one had a better secondary, which starts and ends with Sherman on their best receivers. You know what the Seahawks did last year that none of the other teams with a superior defensive line could do?
Win the Super Bowl.
You conveniently give this last year's Superbowl winners as an example, but history shows that elite pass rushers win superbowls more often. 2013 Ravens, 2012 Giants , 2011 Packers, 2009 Steelers,and 2008 Giants all had excellent pass rushing capabilities.
I also think you are underselling just how good the seahawks pass rush was. The Broncos line had no picnic trying to defend Manning.
To drive my point home, the absolute best CB can neutralize 1 WR. The absolute best pass rusher neutralizes the QB. We saw this each time the Giants played the Patriots at the superbowl. Brady is an all-time great, and pass rush can take him out. Would you rather stop Brady or Calvin Johnson, because all the best CB can do.