The formula for success in the NFL isn't that complicated. You need a quarterback (obviously), you need to protect that quarterback, and you need to get to the other quarterback. Beyond that you want players that are around the ball constantly. Edge rushers are in the backfield more often than ILBs and corners are around the ball more frequently than safeties. You don't want mediocrity anywhere on the field but if I had to choose between strength at wide receiver, corner, and edge rusher and running back, safety, and linebacker, that choice is easy.