Coaching is the major difference between these two teams? Hmmm. I guess Jerry the GM is off the hook.
Russell Wilson < Tony Romo
Seattle OL == Dallas
Beast > Murray, but not by much
Seattle TEs << Dallas
Seattle WR talent < Dez all by himself
Seattle WR depth > Dallas WR depth
Seattle Safeties >> Dallas Safeties
Seattle Corners > Dallas Corners
Seattle LBs == Dallas LBs
Seattle DL >>> Dallas DL
Seattle Punter == Dallas
Seattle Kick Return < Dallas
Seattle Kick Coverage > Dallas
Seattle Kicker < Dallas
Jerry the GM is on the hook for fielding a college backup defensive line, but most of these differences between the teams are in how well the players have gelled together as a team. The talent level is about the same (again, minus the DL).
Jerry the circus ringleader and coach-neuterer is squarely on the hook for creating a circus environment complete with cage-dancers that makes the Seahawks' team-first attitude impossible to cultivate in Dallas.
Seattle's created depth where there was none on paper. Dallas has consistently been unable to teach average players to step up.