Yeah, calling Sharp a pretend center and saying the center depth on the team is shitty is a ringing endorsement for Sharp in the middle.
He is a good 2nd line center and Bolland is a good 3rd line center. And Toews is a pretty decent top center.
edit: to expand on this...
Why should Sharp be on the wing? Because that's where he scores more goals, right?
Why is that? Why does he score more on the wing? Perhaps because when he's playing center, he's playing more of a 2 way game (as Centers are demanded to do). He's taking draws, he's backchecking, he's battling down low. In other words, he's busy being an effective center man. Figure that- a really good hockey player playing the center position the way it should be played. On the Hawks 2nd line. And he's scoring 25-30 goals.
Sounds like a legitimate 2nd line center to me. A 2nd line center, as Iago already pointed out, who was the 2nd line center when the Hawks won the cup.