By now, there is little question about the rivalry between the Seahawks and the Cardinals of the last couple of years (if you need to see the raw emotion, at least from the Cardinals' side, check out the episodes "The Penthouse" and "Endings and Beginnings" of the "All or Nothing series). When you look at the analytics of it, as Bill Barnwell did in this article, the question arises -- is it good to have such a rivalry, or not?
It's not so much about the rivalry itself but the fact both teams are so good. Barnwell points out, through recent historical data, that to have two powerful teams in one division -- the argument can easily be made that the two are among the top four or five in the NFL going into 2016 -- can cost both a significant chance at a Super Bowl win.
Again, it's not so much that the two teams beat up on each other, which can be part of it, but the reality that home-field makes a big difference in the postseason. When two strong teams are in the same division, it's that much harder to obtain. Still, in 2013, when the 49ers were still strong and the Cardinals had 10 wins and the Rams were still doing well in the division, the Seahawks managed to emerge as a Super Bowl champion. And during the season, these days, there is little like Seattle week for the Cardinals.