Always important to go for quality with glasses...
My inferior eyeballs see the reason for Winchester being out of the team is that he is too slow with the ball... Yes he has fairly good close control, but if we want to move the ball around quickly he is more likely to stop, do a 360, beat two men then fall over.
Comparison with Dunn - Dunn knows what he wants to do with the ball before he receives it - Winchester collects the ball, then considers his next move.
At least that is what I see!