I do wonder about his ability to play 200ft hockey as a center, his skating just might not cut it. He's very good defensively on the wing, yes. But defending as the center requires a lot more skating. And if he commits to that defence, is that taking away from his commitment to deep board battles on the offensive zone? If you can give him very good defensively responsible wingers, who are willing to do a bit of extra work I think it could work.
But you know what? Him just taking faceoffs as a winger is an option too. No rules say that the guy who is the nominal center has to take the faceoff. Kakko seems very good at it, so might as well let him have it.