Quarterback Geno Smith
Seattle had several issues this year, of course. The offensive line was inconsistent and never overly good. Offensive coordinator did not seem to call enough plays for the tight end group. The Seahawks rush defense was atrocious and got worse as the season grew old. But overall, and as much as some 12s like to think, quarterback was not one of the main reasons Seattle underperformed this season.
Geno Smith might have had a bit of a slump in the middle of the season, but the Seahawks were also playing some good defenses like those of the Cleveland Browns and Baltimore Ravens, among others. While Smith finished 17th in passer rating, where it really matters, overall quarterback rating (which includes things like completions under pressure, sacks avoided, throwing distance, and others), Smith was 12th.
Smith finished with 20 touchdown passes against 9 interceptions and he led the league in game-winning drives (5) and fourth quarter comebacks (4). In his final four games, Smith threw 8 touchdown passes and just one interception. Smith finished 10th in interception percentage as well. Smith also received the 13th-best grade among quarterbacks, according to Pro Football Focus (subscription required).
My point is not that Geno Smith is not going to singularly lead the Seahawks to a Super Bowl victory but very few quarterbacks ever could do that. He is good enough to take a good team to a deep playoff run, most likely. But the team around Smith needs to be better and the offensive coaching needs to be better moving forward.