well, they did play better defenses. What impactful DE injury did the Lions suffer. As far as the #1 CB injury...if Houston was on Seattle and got injured it would not impact them since he would be 4th on their depth chart.
Talking number 1 CBs. It impacted Detroit having Houston out and also play hurt. If Sherman play hurt he could give up 10 TDs.
Jason Jones(13.5 games) and Ziggy Ansah (2.5 games plus 4 games hurt shoulder).
Detroit has better DTS, DEs are close when healthy, better LBs and had equal safeties. CB is the only Seattle advantage and may be closer now if Houston gets healthy and Slay develops. Seattle lost Thurmond and Browner for good too.