Its a good read, I was just disappointed they didn't give solutions to the spread offense. Seems their is to many great OC and not enough revolutionary DC. The revival of the 3-4 defense to counter these prolific offense seems to fall short. 4-3 is being stuffed by the massive OL's made to give expert QB marksmen 2-3 more seconds to find the target.
I can almost see WR's drafted as CB's and S at this point. But not seeing the evolution of the DL or LB's. I mean do they shrink and look at speed or become more massive. Become taller? Are we going to see 4 300-450 lbs DL's in the future to crack the OL. DL going to look for 4 Wilforks in the future. I just don't know. But as the article eludes to, defenses are getting creamed and behind the curve. Even the #1 defense was rocked in the playoffs.
As has already been noted by Deus and others, the league wants prolific passing attacks and high scoring games. The NFL is all about expanding their market share and fan base, and aerial acrobatics are more popular than trench warfare.
As Cossell notes, it's a chess match between offenses and defenses. Offenses have evolved to create mismatches and the rules make it easier and easier to exploit those mismatches. With all of the advantages that offenses have cited in the OP, there are only so many ways that defenses can respond to make things more competitive:
1. Find ways to get more pressure on the QB. Less time = less successful completions, more errant throws and turnovers, etc. As was discussed in another thread, defenses are already evolving to emphasize interior pressure more than previously:
http://www.patsfans.com/new-england-patriots/messageboard/10/922318-building-team-inside-out.html
We're seeing more and more uber-athletic "Super Grizzlies" in the Wilfork/Ngata mold. The idea of a 330# DE was crazy a few years ago, but its becoming more and more common. Guys like Marcell Dareus and Dontari Poe have ridiculous athleticism and movement skills for their size. We're even seeing more use of athletic DLs in multiple fronts at the college level: guys like Star Lotulelei, Johnathan Hankins, Jesse Williams, and John Jenkins have all played inside and out. Alabama dropped Dareus into coverage at times when he was there.
We'll also more more "outside" guys who are strong and versatile enough to play inside as well, with more NASCAR-like packages. Guys like Jason Pierre-Paul and JJ Watt are capable of playing almost anywhere on the line, and have incredible athleticism for their size. Margus Hunt has played inside as well as out for SMU at 6'8" 295#.
I don't know if we'll see 4 300+# linemen, but we'll continue to see more bigger and more athletic guys up front, and more creative ways to get effective pressure. Give a good QB time and he'll pick any defense apart given the current rules and the talent available at the skill positions.
2. Create confusion. If you can generate effective pressure and confuse QBs as to the defensive coverages, then you magnify the potential for mistakes by the offense leading to big plays on defense. Ameboid and semi-ameboid schemes will become more common. Morphing from a 4-2-5 to a 2-4-5. Moving guys around - outside guys inside, inside guys out, LBs dropping into coverage, DBs moving up, CBs and Ss being used interchangeably. If the QB has little time to make a read and the defense has more disguise, then it will be harder for the offense to find the right mismatch, even if one exists.
3. Increase your coverage options - use more DBs and coverage LBs. The nickel is the base, and the dime is the nickel. As BB has stated, you can never have too many good DBs. If you can generate pressure with your front 4, that gives you much more freedom to increase your coverage options with the other 7 guys. 5 DBs will be the norm, and 6 will be more common than 4, along with a coverage LB. Hybrid DBs with size, tackling ability, ball skills and the ability to play zone or man coverage will be coveted. So will LBs with processing speed and the ability to cover like DBs - hence my intense interest in Lavonte David heading into the 2012 draft. Guys like Sean Lee - who actually can drop into coverage effectively and handle most RBs and TEs - will be very valuable. DBs who are tall enough, big enough and agile enough to match up to the big WRs and mobile TEs will be coveted - Brandon Hardin went from a late rount to a top 80 pick in the 2012 draft. Your safeties have to have CB coverage skills - one of the reasons the Pats took Tavon Wilson in the 2nd round. The Giants used S Antrel Rolle - like Wilson a former CB - to cover slot receivers at times. Those guys are also big and physical enough to play as hybrid S/LB types - a role that the Pats have reportedly already had Tavon Wilson playing during OTAs and mini camp. Tony Gonzalez has suggested that teams need to look to basketball players for guys with the kind of height and footwork to covert to DBs:
Falcons tight end Tony Gonzalez joked that there are so many agile tight ends that teams may have to start scouting basketball games for safety talent. "Maybe they should find some 2-guard types, 6-foot-4 guys who can match up with tight ends," he said.
NFL shifts from big, physical safety to a more versatile model - ESPN
That article is another great read for anyone interested in the challenges facing defenses in the modern passing era given the constraints addressed in the OP of this thread.
There's not many more things that I can obviously seeing defenses doing, short of putting 12 men on the field. And I'm firmly convinced that the league doesn't want them to succeed - they want football to go the way of fast break basketball. I'm personally convinced that if DCs found a way to consistently shut down today's offenses, the league would tweak the rules to make it harder.