He did reach his full potential, what's underwhelming is the fact that his prime lasted 3 or 4 years max.Could see him retiring. Already won it all and doesn't seem really have the drive to keep playing like a Ramos or Puyol who both also won it all but played until mid/late 30s.
You almost want to say he never reached his full potential but his trophy cabinet says otherwise. Still imo, there is something super underwhelming about him.