In this day and age, there are more "surprise" Super Bowl teams than in the past because it's hard to build those consistently dominant teams and keep them together. I won't count the team out from that standpoint, but the defense definitely puts us on shaky ground, enough so that I wouldn't feel comfortable predicting a Super Bowl appearance even if we stay healthy.
I do think we'll return to being a playoff contender if we stay healthy and frankly, if you can get into the playoffs, a few good breaks can put you in the Super Bowl. Dallas is going to have to be just as good as it was on offense in 2014, though, to get into a position where those breaks can happen.