He's honing his abilities well but I don't think he's found the right role for himself yet. He plays as a pivot yet isn't great defensively and that furthers him from our passing play. If he were to push up, he'd need to develop more mobility and demand the ball more often. He doesn't have to be a carbon copy of Xavi or Busquets but he does need to find the place and style for him that allows him to constantly shine and boss the midfield in his own way and utilize the brilliance that so far has been shown in flashes.
To sum it up, he has done well, but hasn't shown his best yet.