OK, now that you're all up to speed, let's start out with the heartwarming tale of Mike and Robert...
Washington 2011 & 2012
Mike Shanahan was in trouble. Teams are supposed to get better in the second year of a coaching gig; his team had gone 5-11 in year two after going 6-10 in his first year. He had an excuse; after all, with Rex Grossman as your team's QB (for you younger fans, think Brian Hoyer), your offense is bound to have some issues. Coaches brought in with the expectation of returning a proud franchise to championship level competition don't deal in excuses, though. Neither do the team owners that employ them.
Mortgaging their future by gifting the St. Louis Rams multiple draft picks, they traded up to the 2nd overall spot behind the Colts and took Robert Griffin, III. RG3 was the "other" QB besides Andrew Luck in that year's draft that was considered a potential face of a franchise. The move paid immediate (and short-lived) dividends.
The team's offense improved from 26th in the league in scoring to an astonishing 4th. RG3 won rookie of the year honors with his 65% completion percentage, 3,200 yards passing, 20 TD's, and a mere 5 INTs. He also had 815 yards rushing with another 7 TD's. In short, it was one of the best years a rookie QB has ever had in the NFL; statistically, it was better than Luck's. The team also struck gold with rookie running back Alfred Morris, who rushed for 1,600+ yards that season.
This offensive explosion offset a small regression by the defense (they lost Brian Orakpo for the season in training camp) and their 10-6 record won the NFC East that season. The lost their playoff game against the wild card Seahawks at home, with RG3 sustaining a serious knee injury in the process. He has not been the same since.
Vikings 2011 & 2012
In 2010, Zygi Wilf grew weary of watching Brad Childress pushing the bounds of mediocrity and fired him mid-season. He was replaced with Leslie Frazier and brought back in 2011 to see what he could do with an entire season.
What he could do in 2011 was terrible; a 3-13 record, one of the worst defenses in the league (31st in points allowed), and a QB (Christian Ponder) that looked awfully shaky in his rookie year. The plan had been for Ponder to learn from a 35-year-old Donovan McNabb for a year or two and then let him loose on the league. As it turned out, McNabb had nothing left in the tank, and Ponder was thrown into the fire after Game 6. The results were fairly predictable.
Frazier was brought back for another shot at success. The team parlayed their high draft choices into a new left tackle (Matt Kalil) and a new safety (Harrison Smith). They reworked the O-line; 4 of the 2011 starters were replaced or moved. In addition to Smith, there was a new starter on the d-line, a new starting LB and some skill players added. The team did choose to bring back Ponder (he had no serious camp competition) and still had Adrian Peterson, but he was recovering from a knee injury. Going into the season, there were a lot of questions about whether he would be as good as he had been before.
2,097 yards and 12 TD's later, the questions about Peterson would be answered with his career year. The passing game regressed in Ponder's second year. The team's total offensive yards increased by a paltry 110 yards from 2011 to 2012, despite Peterson's assault on the single-season rushing record. The offense did get more efficient in 2012, increasing from 19th in scoring to 14th.
The real change happened on defense, though. The Vikings scoring defense was able to improve to 14th in scoring defense from the 31st of the previous season. This and the rushing offense were the two largest changes that happened with the Vikings. To give you an idea of how dominant Peterson was that season, there were eight games out of the 17 the team played in 2012 that the Vikings had more rushing yards than passing yards. The Vikings were 5-3 in those games, but one of those three losses was in their playoff game.
It is also worth noting that their kicker (Blair Walsh) was the NFC All-Pro kicker in 2012. He went 35 for 38 attempts, including 10 for ten on FG 50 yards or more. SoS and turnover margin did not change from 2011 to 2012 for the Vikings. Their QB and coaches remained the same and in that respect, they are unique among the seven teams that had a five game or more jump in their records after horrible seasons.
What About The Bolts?
In 2015, the Chargers defense ranked 21st in the league. That was the worst year on Pagano's (4 seasons) and McCoy's (3 seasons) watch. While that does sound bad (and it is), from a pure bean count standard, the Chargers main problem last season was the offense. That unit finished the season 26th in scoring. Putting how truly godawful that was in perspective, the last time the Bolts finished a season in 26th place in total scoring, the leading passer for the Chargers that season was a QB named Ryan Leaf...
The ranking also matches the one by Washington in 2011 with Mike Shanahan coaching a team desperate enough to start Rex Grossman at QB, with Ray Helu the team's leading rusher.
From a non-bean count perspective, I have already offered up my opinion about what went wrong last season. This review only reinforced that opinion. The season point differential indicates that the team underperformed by two wins in 2015.
Looking at the QB and coach combinations in the teams that had the horrible years, it's obvious that not one of the teams in the crappy season had a QB that was even close to the ability of Philip Rivers. I think we can agree that PR was not the problem last season. I would not have believed before last year that a team with PR at QB could go worse than 6-10. I also note that the replacement QB's (in two cases rookies) were not in the same class as Rivers.
In a league of parity and across the board ability, it often comes down to coaching. The Chargers still need a good one. The team might get better, but I would put money on them not getting five games better. Simply put, the Chargers stayed pat with their coach and QB. According to the usual way drastic turnarounds happen, it will not happen in San Diego this season. Any improvement coming will be marginal, something along the lines of 2 or 3 games.
By choosing to retain McCoy, we fans are hoping that the same magic that Leslie Frazier conjured up in 2012 might migrate to San Diego in 2016. Anybody see a 2,097 yard year coming from Melvin Gordon? Yeah, I didn't think so. Of course, PR is a much better QB than Ponder, right?
One last word on Minnesota and Washington. Neither team could sustain its success after the bounce back years. Both Shanahan and Frazier were fired after the garbage seasons their teams reverted to the season after the comeback year. Indy, AZ, KC, and to a lesser extent Philly have stayed above average or within a game of .500 since their coaching change (we'll see what happens to the Jets). In the financial world, this is called "sustained growth." Minnesota and Washington followed a pattern that investors would know as "a dead cat bounce."
There is some optimism I have to offer: If Dunlap returns (and stays healthy), and Slauson or Tuerk win the starting center job, there are the two new o-linemen that the bounce back teams had. The 2015 SoS was 2.2; that MIGHT BE less this season, although the Bolts could be in a similar situation to that of Arizona in 2012 and 2013 (i.e., sharing a division with two loaded teams). A replacement offensive coordinator was brought in (and it is unlikely any GM will be interviewing him for a head coach gig anytime soon). The defensive personnel will have four new starters (at least). There will be three new starters (at least) on offense.
Will that be enough to boost the team to a 9-7 or better record? Based on recent NFL history, it probably won't be. I hope I'm wrong.