I disagree, I think Scandrick is a good player, he does a good job covering guys in the slot. I don't see that, he's certainly a good player, but I didn't even think he was the best corner on the Chiefs. Brandon Flowers holds that title. I think it's pretty clear-cut the Jets have superior CBs (probably the best trio in the league) but if Claiborne has a good rookie year the difference could be negligible. Where the difference won't be negligible is OLB. Ware is obviously one of the most disruptive players in the NFL, but even Anthony Spencer would be the best OLB on the Jets. Having a pair of quality pass-rushers can make the rest of the defense look better then it really is. Ultimately, I don't see enough difference in talent to confidently rank one over the other, but I do think the Cowboys will appear to be the better defense because of their offense will put them in a better position to succeed.
rob ryan will lead the better defense only because he will be the only one leading the defense. rex is a head coach he doesnt lead the defense he leads the team. rob on the other hand is the defensive coordinator and leads the defense. now a mike pettine vs. rob ryan might not sound quite as catchy but would be a much better comparison.
Only advantage personnel wise for Cowboys is at OLB in their base 3-4. Maybe also their Safety tandem, but a healthy Laron Landry could be good for us especially in the 46.
Don't be fooled into thinking that Rex doesn't have significant influence on the defense. Pettine may be the go to guy and call some plays, but it's still Rex's D and he did say that he was going to be more hands on with them, this year.
Scandrick is a very good slot cover corner. Where he struggled was when they had injuries and he had to move up the depth chart to the outside. He's very good if left in the slot. There was a time a couple of years ago where you could almost not throw the ball on the chiefs with those two corners, yet no one really talked about it. I'm not sure what's happened the past few years, but they seemed to decline. Regardless, I'm a big fan of both Flowers and Carr. I agree with everything else you said. At first, from memory, I though the Cowboys had more talent. But when I looked at their depth chart I realized that wasn't the case and it was pretty even.