I don't know if Bradley was to blame. I'm just open to the concept. I still remember Philip Rivers having a career record day against our defense in Seattle back in 2010, and Pete turning to Bradley and pretty much just said "wtf is that?" If Bradley was involved, there is certainly a chance he could have contributed to the problem, and if he wasn't (if he was just a figurehead) then exactly what did he do anyway? I don't think he was a figurehead though- I got the impression that Pete trusted Bradley with playcalling and appeared to be given input.
Of course, it's Pete's blueprint. Pete made the call to switch to press after 2010, and he also handles in-game adjustments.
At the same time, I don't think Bradley was any more or less involved with the defense than Bevell is on offense. Pete fired a talented OC because (in part) he refused to run the ball more, which if you watched the 2010 season, you'd wonder what Pete was thinking because the Seahawks O-line and run offense were both among the worst in the league. Seattle's offense went from the 20s to #1 in FO's efficiency rankings in just 1 year, and though I like Bevell, I think he gets minimal credit for that. Most of it goes to Russell, though even with T-Jack our offense would probably be top half next season. Pete is just as much a genius at offense than at defense, but he can't do it all, and some control is ceded. Pete doesn't call the plays, but he does just about everything else.
The one thing I will blame Pete for is his over-emphasis on specialists on the D-line. Pete is so obsessed with stopping the run that for the majority of downs the last two seasons Clemons was our only real pass rusher, they were hesitant to blitz as well.
So who's fault is it for the lack of blitzing? Seattle blitzed aggressively in 2009 but I sense that was on Jim Mora (who constantly preached about wanting aggressiveness and dirtbags). Seattle blitzed less in 2010 than 2009, less in 2011 than 2010, and less in 2012 than 2011. Now Quinn comes in and the first thing he talks about is being "aggressive" on defense. In every interview he does he talks about aggressiveness and pressure in almost every sentence. Not long after that, it was revealed that the team was modifying the SAM position to make it much more pass rush oriented and much less run defense oriented. Was that Pete's idea or Quinn's? I guess we can't know for sure, but the indications point at Quinn.
My view of Pete is, he's like a NASCAR owner. He builds the best car he can, he hires the best pit crew he can, and he recruits the best driver he can find, and he might even give suggestions to the driver during the race, but in the end, he's not the one behind the wheel.
As far as coverage goes, part of it is just mental breakdowns by young players (Sherman in final seconds of regulation vs. Chicago), part of it is a flawed pass rush, and part of it is playing "bend but don't break" defense. The last of which is in Pete's blood as he's a Kiffin disciple, but so was Bradley. It sounds like Quinn might have more of a risk taker philosophy with his defense. If Pete cedes control to such a degree, then it wouldn't matter if it really was Pete's fault in the first place as doing so would mean Pete signed off on a step in a new direction.
Maybe I am terribly wrong and/or disgracefully full of shit. But I don't think it's possible to know until next season is over and we've seen the differences between a Gus Bradley defense and a Dan Quinn one.