No one is dismissing Demidov at center, we are dismissing the notion that they'd put him there in his rookie season. He's going to come in and rightfully slot at the place he's been playing his entire professional career, which is on the wing.
Plus, you don't need to be the center to play like a center. The goal is to get someone in the vein of a ROR or a Couturier who can do the faceoffs and heavy defensive responsibilities, then let Demidov take the puck and do all of the offensive aspects that a center has.