Looking at the AFCCG again (boy it was painful), here are a few reasons why the Broncos just crushed Brady. 24 QB hits - the most in the NFL in any game since 2006 - almost 10 years. That's crazy.
1. Injuries. Let's start with the obvious. The OL play was not helped by injuries. Nate Solder, a borderline pro bowl-caliber LT, was lost for the season. Ryan Wendell, a starting guard, was lost for the season. Sebastian Vollmer, a 2010 2nd team all-pro at RT, was banged up and missed several games, and had to move to LT to replace Solder when Solder's initial replacements were ineffective. Bryan Stork, the starting C, missed 8 games, and at times had to play OT - a position he'd never played before. For much of the season, the Patriots were playing with Marcus Cannon and Cameron Fleming - a practice squad player to start the year - at T. The Patriots used the most line combinations in the NFL. The original projected starting lineup for the season was Solder-Wendell-Stork-Kline-Vollmer. It ended up in Denver being Vollmer-Kline-Stork-Mason-Cannon. Two starters out, key guys playing out of position...the OL was a total mess. They played three rookies at times (Mason, Andrews, Jackson). They played practice squad guys (Fleming). They played guys they picked up off the street during the season (Waddle). There was no consistency and the talent was either inexperienced or depleted by injuries.
2. No running game. The Patriots were not a good running team all season long, finishing 30th in rushing yards per game (87.8), and 29th in rushing yards per attempt (3.7). But the running game suffered tremendously when their top two running backs, LeGarrette Blount and Dion Lewis, got hurt. The last 5 games of the season, the Patriots rushed for 93, 63, 70, 38, and 44 yards (61.6 yards per game), and lost 3 of those last 5. Blount had averaged 4.3 yards per rush, and Lewis 4.8, and without them, the Patriots were left with Brandon Bolden (3.3 ypc), James White (2.5 ypc), Joey Iosefa (3.4 ypc), and then picked up Steven Jackson off the scrap heap (2.4 ypc). In other words, the talent level at RB once Blount and Lewis got hurt was just abysmal, in terms of running the football. Reports have surfaced explaining what was one of the most inexplicable losses in recent memory - the week 17 debacle against the Dolphins. Apparently Belichick was (rightly) very concerned about the running game - or lack thereof. And he wanted to use that Dolphins game to focus on the rushing attack, believing that the only way they'd have a real shot at winning the Super Bowl would be to get at least some semblance of a running game going. Miami came out in nickel and dime heavy formations, and the Patriots STILL could not run the football, even though they kept pounding away at it. Once it became clear that the Patriots could not run, they went pass-heavy in the second half but still lost what turned out to be a crucial game. The lack of a running game allowed Denver to pass rush on every down, not worried at all that the Patriots would have success on the ground. Being totally one-dimensional against a defense like Denver proved disastrous.
3. Immobility of Brady. Brady has never been mistaken for a Randall Cunningham, a Steve Young, a Fran Tarkenton, a Russell Wilson, a Michael Vick, a Cam Newton. That is, he's not a runner. But against Miami, his mobility dropped even more when he suffered an injured ankle. It was not healed by the Denver game, and that left Brady very vulnerable. Scrambling was more difficult than normal, even though he did manage an important 12-yard run during the game. He moved less effectively in the pocket, and the Patriots never tried to move the pocket. As a result, the Broncos could send their ends sprinting around the tackles to a single spot on the field, and Brady was almost always there. Brady's even greater immobility hurt considerably as he was unable to avoid the rush.
4. Quick-strike options were injured. Edelman. Amendola. Dion Lewis. One way to counter a great pass rush is to get rid of the ball quickly. The Patriots' main options in this aspect of the game were all injured. Julian Edelman, perhaps the quickest receiver in football, was clearly still hobbled by a broken foot and was not at all his usual self. Danny Amendola was banged up and not at all 100%. And the revelation of the early season, Dion Lewis, who had averaged 10.8 yards a reception, was out for the year. That left the Patriots with only Keyshawn Martin as a quick-strike option. Against Denver, Martin had zero receptions on just one target. James White, a poor runner but solid receiver, was targeted 16 times, but several long wheel routes came up just barely empty as Brady did not have enough time to throw. The quick-strike options were severely limited, forcing the Patriots to use more traditional modes of attack, but Brady simply didn't have enough time.
5. No attempt to use Denver's rush against them. This was on the coaching staff. Typically, you can counter a heavy rush by running the ball, throwing screens, running jet sweeps, or using trick plays. The Patriots ran zero trick plays, and virtually no screens. They ran no jet sweeps, and could not run the ball. They simply kept dropping back to pass. When it is clear that your regular stuff isn't working, it's time to try something else. Denver's defense played a fantastic game, able to get pressure with just 3 or 4 guys, dropping 7 or 8 into coverage, so running screens against that kind of defense would be admittedly difficult. Nevertheless, they did not attempt to use the Broncos' heavy pass rush against them, by countering with plays designed to take advantage of the Bronco defensive ends getting so far upfield. It was one regular pass after another, with Brady dropping back to the same spot on the field.
6. The snap count. The crowd was electric all game long, and the noise they generated prevented the Patriots from altering the snap count or using a hard count to draw Bronco defenders offside. If the game was played in Foxboro, there is no doubt that Brady's cadence would have drawn at least one penalty, and if nothing else, would have made Bronco pass rushers pause at least a fraction of a second, and that fraction of a second would have been enough to complete two of those wheel routes to White.
What's interesting, of course, is that all this, plus a phenomenal game by Denver played by a highly talented defensive unit, and the Patriots STILL would have been tied at the end had Gostkowski not missed his first PAT since 2006. Moreover, the Patriots still out-gained Denver, 336-244. It was the 5th most yardage given up by Denver all season, which is remarkable given all the factors listed above.
The question is: Which of these things can change in 2016? Well, injuries are what they are, and there's no way to predict. Maybe Lewis and Edelman are healthy all year, but they suffer more injuries along the offensive line. Maybe Gronkowski misses a lot of time. Who knows. The running game was much better with Blount and Lewis on the field, so getting them back could by itself be a factor. The health and improvement of the offensive line seems of paramount importance, not only for pass protection but also for run blocking. Can the young guys take the next step forward? Can Solder and Vollmer stay healthy, thus keeping Cannon and Fleming on the bench where they belong? Can the Patriots secure home field advantage so they don't have to deal with the crowd noise?
The Patriots have the pieces to fix all these problems in 2016. Health is the key.