its definately a player who i like to have, and i think many people out here. He is very good fespecially when you consider his age, and there is definately still a lot of room for making him stronger with the potential.
The problem with descirbing the perfect SF is, that there are so many different types of SF who are effective.(i like to say that you can not waste training on a sf because he needs every skill somehow)
Personally i like to have the sf some play making ability, so i would push his passing and his handling with 1 on 1 training.
Defence 13+/11+(OD/ID) would be also basic, but after this you could go different ways making an Inside SF with lot of IS, RB 1 on 1 training and little bit JS. Going balanced in pushing his jumper to ~13/9(JS/JR) and then train all offensiv skill equally. But i wouldn't make an outside SF out of him, because for me he is to big for that.