There is a lot of parity in the NFL these days. Any team can beat any other team any week. While it is evident that the Seahawks are not the team that they were 2 seasons ago, they are still one of the better teams in the league. I believe that their defense is just as good as it used to be, especially with Cam Chancellor back, the problems, in my opinion, are with the offense. The NFL is a learn from last season type of league, and I believe that the other teams have Russel Wilson, and their offensive tendencies figured out.
That said, I still feel that the Seahawks have enough talent on both offense, defense, and special teams, along with previous playoff experience to make the playoffs, it may be as a Wild Card, but they will get in.
After a tough loss to their division rival the Arizona Cardinals, the Seattle Seahawks still have a very good chance at making the playoffs because of their remaining strength of schedule. The Hawks have seven games left, four of which are at home, and get to play the 49ers, Ravens, and Browns, who have all struggled this season. Their toughest challenges will be against the Steelers at CenturyLink, at Minnesota, and at Arizona. Most likely, Seattle will finish the season at 9-7, making it a likely contender for a Wild Card berth.
In the world of sports, every team has a chance of winning. In the case of the Seahawks, they would not be in the league if they were not qualified and up to the standards of the tournament. They are professionals and therefore they have a chance of making it to the playoffs.
Although they seem to be working very hard, they still seem to be having a lot of bad luck. Maybe they can pull it off but it doesn't seem very likely that they'll make it to the playoffs. I hope they will though because they are working very hard and putting in a lot of effort.