No manager is going to improve Ross Barkley that much.
His problem is that he lacks intelligence, both on the pitch and off.
Let's face it, leaving Everton right now, with Rooney's arrival and finally having some financial muscle to bring in players who can compete at the top level, is not an intelligent move.
As for playing, sure he has talented feet, is strong and quick but his decision making is slow and ponderous because his brain doesn't work fast enough for top level sport.
He can't look up, have a picture in his head and play a pass like Rooney, Tom Davies, Kieran Dowell or Gareth Barry and that slows the play of the team down. It appears that Klaassen also has this ability so we just don't need Ross any more.
Yes, he is an Evertonian but we have plenty of young blues chomping at the bit to pull on the blue shirt with plenty of talent and better still, they appear to have intelligence and a knowledge of how the first team wants to play. Something Ross Barkley never seemed to get.
Let him go and let's see if the grass is greener for him elsewhere.
I sincerely doubt it though.