This is an article from Grantland, a website from ESPN's Bill Simmons.
Basically, it discussed what we all knew.
1. The Dolphins underachieved last year.
We were terrible in games that were close.
Statistically, it's very rare for a team to lose 4 games by a FG or less, as we did against the Browns, Broncos, Giants, and Patriots.
We were 2-5 in games decided by a touchdown.
2. We had a horribly difficult schedule considering our 7-9 finish the year before:
We only had 5 games against teams with losing records.
Football Outsiders rated the Miami schedule as the league's sixth-hardest last season.
Good news: This year, the same site projects the Dolphins to have the eighth-easiest schedule in football.
3. The improvement in our team's performance came from the improvement in our defense, specifically the improvement in our pass defense from bottom 5 in games 1 to 8 to top 5 in games 9 to 16. He credits a lot of that improvement to Vontae Davis, who missed 4 games and left 2 others early due to injury in the first half of the year but was mostly healthy the second half.
I agree with him for two reasons:
First: Vontae Davis is a pretty good CB
Second: Our backup to Vontae Davis, Nolan Carroll, was terrible
So getting Davis on the field and Carroll off the field leads to huge improvements.
Now, I don't agree with all he wrote - for example, he argues that the Dolphins would be idiotic to go with Garrard over Moore given Moore's performance last year and Garrard's injury history, but he hasn't been seeing the difference in their quality of play the entire offseason.
Still, he makes some good points overall.