The Seahawks wont make it to the playoffs one reason being the way they started their season off last year. They showed the world that they can be beaten. They started off their season with an 0-2 losses with the St. Louis rams beating them then the green bay packers for the second. Also the NFC is heating up with other teams like the Panthers having their record twice last season. And the cardinals who are looking to get back to the NFC championship and hopefully win it all. Also teams like the Cincinnati Bengals and the Carolina Panthers beating them they have slim chances they'll make it back to the playoffs. Also they will loose a number of good talented players to larger teams. Players like Doug Baldwin and Jermaine Kearse being locked onto different teams radar and eventually leaving the seahawks tight end and receiving positions pressured.
I agree the NFC West is heated up but really the only threat is the Cardinals. Seattle has made it back to the Play offs due to the Defense they have, but this season the defense will get help from the offense. Russel Wilson and Doug Baldwin will have that connection through out the year like they did the second half of the season last year. Seattle is one of the biggest threat to the NFC, if Seattle maintains a excellent defense and a comeback offense then they will make it back to the play offs.