Yeah. I'll add his defensive issues have been there his whole career. It isn't to blame on being in a poorer team, though he has on the odd occasion been left stranded by his inside men. He is approaching the stage in his career where he really should be improving an obvious weakness.*edit, I read your post above. Some good points there. He certainly has weak areas in his game that he needs to work on.
I was going to write as yet I haven't seen any improvements, but that wouldn't be quite true. The opening month I was praising him and saying I'd judged him wrong as a player. Since then he has fallen back to old habits. So I don't think there is no hope he can improve this aspect but I do think it will be a continual concern.
I also think he has physical limitations that mean he will always need those inside him to create for him. He doesn't have the physical attributes to change games himself.
He is pretty quick but not a genuine speedster. He is pretty strong but not a genuine power runner. He is pretty agile but not a genuine mover. And he is no aerial threat.
The elite wingers can change the course of a game with one of the above. Turuva can not. I understand he isn't being paid elite money but he is on the next tier down money wise. As such I think he needs to improve his actual weaknesses to perform to that level, given he doesn't have that little bit extra to his game to offer.