Well if I remember right, he was used as an attacking midfielder or out on the left. Not quite the Rooney role. Even at Porto, he had a nasty injury which kept him out for a while and kept him from playing all that much for 'em.
Having said that - I don't think that we should play people solely in the positions they were in when we signed them. That would just be silly. He needed to improve his all-round game which he has done, though again injuries have stunted his development. Also, to fit into the system we play, he had to add discipline and defensive know how to his game. He has all the qualities to be a top quality box-to-box midfielder. We've seen how dominant he can be there in patches. Also, there is no way he was going to displace Wazza in that position behind another forward or Kagawa now. I definitely think CM is the best position for him...
Now can we get him to follow Giggy's example and take up yoga or something? Honestly we should try everything to ensure he stays fit for a prolonged period.