Going into this season I thought it was wide receiver. That still could be the strength, but Parker hasn't emerged the way it was expected. Plus, who knows if the team keeps Landry.
Right now, I'd say defensive line. Suh is a dominant DT, one of the top five in football. Wake is still a 10 sack a year guy. Godchaux was a quality rookie and Harris has potential. That said, it's still a position I'd add to since the best players are older veterans.