There's something to be said that Vision's presence may be more than just him being a figment of Wanda's imagination. What if this is all happening in Vision's head and Wanda is there trying to keep it all together? It would explain why Vision seems to be gaining more awareness as time goes on as if on the outside he's learning more and becoming more of himself. The only damper on this theory is that this is about Wanda's journey, not Vision's.