One of the topics which has generated the most questions for me in this column has been the rise of offensive football, the seeming tilt of the balance in favour of the pass, and against defenders. It speaks to the way the game evolves, of course, and we might read into it any number of wider points, from the presumably shorter attention span of the electronic generation to the correlation between gaudy passing and receiving stats and everything from bigger contracts, appearances on highlight videos, and election to the Hall of Fame.

But it's crucial that we keep this changing balance in mind when we look at the game, because sometimes patterns that once seemed set in stone get altered. One of the effects of the continuous opening of passing games has been a change in the nature of the personnel you use on defense. We've also had an inordinate number of questions from Bears' fans, and one I received last week on twitter (@carlsonsports) highlights this change in defensive mind-set.

What did you think of the Bears' pick of Shea McClellin in Round 1 of the draft? It shocked me.

Steve Henderson (DaBearUK)

It surprised me too, Steve, but not for the reason you might think. I was convinced McClellin would go to a team playing a 3-4 defense, because he is a talented pass-rusher who is somewhat undersized for a 4-3 end, but athletic enough to play in coverage. Sort of a more explosive Jarret Johnson type. But the 2012 Draft was defined by the emphasis placed on pass-rushers and shut-down corners, the two most important positions when you're plotting how to stop the pass. People were truly shocked when Seattle took Bruce Irvin with the 15th pick—and he may or may not work out—but what the pick said was that a pass-rush specialist, like a nickel corner, is someone you're going to use so much that he might as well be considered a starter. Indeed there are a number of teams that played more in their sub-packages than in their 'normal' alignment.

Plus the pick makes perfect sense when you recall that Lovie Smith's teams play the Tampa-2, and their ends are not necessarily asked to be run-stoppers. Julius Peppers is perfect for them (or anyone) because he's a great one-on-one rusher who can also seal the corner (Simeon Rice played the same role on Tampa's best defense from the past decade) but no one worried about Dwight Freeney or Robert Mathis' inability to stop the run, and Tampa had the undersized Greg Spires on the other side from Rice. In that defense you can play the end wide, to isolate the offensive tackle on an island, and allow a true one-on-one rush (Philadelphiauses this approach with what last year was called the 'wide 9'.)

I think McClellin's going to show more ability as a conventional end anyway, but he was drafted for his pass rush, and reports from the camps indicate the Bears are very much satisfied with what they got in the draft.

Who is the greatest coach of all time?

Darren Moses

I love historical questions, and always preface them by trying to explain the difficulties involved in answering them accurately. When it comes to coaches, we're looking at two things. There is the coach as leader, those who knew what they wanted from their football players, and were able to put players in the right position to succeed, and motivate them to do that. Vince Lombardi might be the best example of that—his philosophy was to keep things simple and execute them to perfection, and no one was a better motivator. I put Bill Parcells into that category, maybe Bill Cowher too. Then there are the innovators, who changed the game, stayed ahead of the curve, or re-drew the curve for everyone else. Some of them, like Clark Shaugnessy or Don Coryell, were sometimes thought to prefer making their offenses work to actually pushing teams over the hump. Sid Gillman on offense and Don Landry on defense were masters who also could pull teams together at the right times, but not often enough (each had a nemesis to keep them in check).

There is coaching for the season, turning in a fine performance year in and year out (Tony Dungy, Jim Mora), and managing a single game (the category where Andy Reid, very good at being consistent, sometimes falls down). And there is always the question of life time achievement (Don Shula) versus peak performance (Chuck Noll or the much underrated Hank Stram). George Halas, for example had a career whose valleys more than outweigh the peaks when it comes to putting him at the top of the pantheon, while Tom Coughlin is fast becoming another Weeb Ewbank, whose ability to win a couple of unlikely big ones elevates his overall rating. Finally, there is also the perception that some great head coaches are more like CEOs of corporations, or generals with overall command, leaving the stuff on the field to their assistants—Jim Lee Howell with the New York Giants left to offense to Lombardi and his defense to Landry and that worked out pretty well for him. And of course there's always Al Davis, unclassifiable.

The greatest coaches are able to combine talents, and I find my top three very hard to separate. One thing they have in common is that they all had complete or almost complete control of their teams, in terms of personnel decisions as well as on the field. We've seen many fine coaches, Mike Holmgren, for example, who've been far more effective working with a talented GM than when they've sought the freedom to be their own GM. Paul Brown was an innovator, both on the field and off, inventing many of the elements that define modern football: assistant coaches, playbooks, film study, calling plays from the sideline, even facemasks. With QB Otto Graham (who hated Brown's calling his plays) he went to ten consecutive championship games, in the AAFC and then in the NFL. After Graham, he managed to win only one title with Jim Brown as his star, but saying 'only one title' is hardly strong criticism. Brown also was an early integrator of the game: his AAFC teams featured black stars like Marion Motley and Bill Willis ahead of the NFL. The biggest criticism against him may be that he failed to alter his autocratic style as the game changed and players demanded more autonomy, and his later Browns teams suffered.

The biggest mistake of Brown's coaching career may have been not handing over his coaching job with the Bengals to Bill Walsh, who was his offensive coordinator. (As an aside, how would you rate the decisions of Art Modell, who bought the Browns and soon fired Paul Brown, and later moved them toBaltimore, on the scale of putting him into the Hall of Fame?). Walsh of course invented the west coast offense inCincinnati, turning Sid Gillman's vertical concepts horizontal out of necessity. Walsh was a keen judge of talent, who knew exactly what pieces would fit into his system, on both sides of the ball—his 49ers were masters of signing the aging veteran hired gun who would get them over the top (and in later years of bending the NFL's contract rules to do so). Walsh also understood the changing nature of the game better than anyone, and on the NFL rules committee helped bring about the rules that made the league a passing league, and helped his own offense to flourish. Walsh was also one of the greatest of players' coaches, hard enough to motivate and flexible enough to be liked as well as admired.

Bill Belichick has created a team that has been almost as consistently successful as the Browns of 1946-56, and in the context of the bigger league, probably more impressive. He's a student of the game, and as such acknowledges Brown and Walsh as models (and, I believe, the strong influence of George Allen's team-building strategies too). What he has done in New England has been to create a consistency in a competitive system specifically designed not to allow such consistency, by, like Brown, establishing his systems, and like Walsh, finding players who fit those systems. He's also shown great adaptability, first by altering his systems to fit his personnel, trying to avoid asking players to do things they aren't capable of doing, and second to stay ahead of the tactical curve. The results on the field are evident, and only two losses in Super Bowls to Tom Coughlin's Giants mitigate against his universal ascension to the greatest coach ever post. What also intrigues me is the Belichick persona, which on the surface is so unappealing to the outsider (and I am not referring to 'spygate' here).

I firmly believe it is a lot easier for a coach to be hard with a team, and then relax, than to be easy-riding with them and then try to harshen. Easy-riding can work with self-motivated, unselfish, smart players, but the modern game encourages the disease of 'me', and odds are against you. Belichick's approach to team-building has been relentlessly 'business-oriented', and his players either buy into that mindset and win with it, or are gone. He's not as cold and standoffish as he appears, but has to maintain a certain distance in order to be able to do what, in his frequently repeated mantra, 'is best for the team'. The smart players love him and understand that they may be cut the next day if they are no longer effective, or, more importantly in the modern game, cost-effective. He understands that side of the business better than most GMs while still coaching better than most coaches.

The evidence for the quality of those three coaches is the spread of the family trees—Walsh comes directly from Brown, and Walsh begat a huge number of successful coaches. Oddly, Belichick's tree includes more successful GMs than coaches, which may in itself be a good argument for the value of his own coaching. When I started writing this long answer I was prepared to rank my top three Brown, Walsh, Belichick. Now I may have put Walsh into first, Belichick second, and Brown third. You can order them any way you want, but I am convinced they are the top three.