Not if you take into account improvements made by the other teams. You could argue that the Packers are better than us and the Lions have made enough improvement to challenge us our spot. Therefore, adding a #1 receiver could make it true that it would allow us to "compete in the division".
After reading multiple posts of defiant, he specifies many different reasons why adding a number one receiver would help Cutler and the offense. His offering of comparisons to the other teams' divisions was not, in my mind, reasoning on why we need a number one receiver. i.e. he wasn't saying we need to get a number 1 because the Lions have Calvin Johnson. He was just saying that if we get one, our receivers would be comparible to the other teams.
So, would a #1 receiver help the team? (I like the Steve Smith idea, myself) yup
Do we need one to compete? We might, depending on how the off season pans out for us and the other divisional teams.
Do we need another lineman to compete? same answer as above
Do we need a corner to compete? same answer as above