Dude, just because he
chose to make them similar does not mean that's wrong. It's more the fact that most of his
fanart
choose to make them different. Ninten's art never has him officially wearing that bandana or having different clothes. That whole rendering is a fan creation.
and
Those are the official pictures. The only major difference is the hat direction (left vs right...) and the backpack.
And Shin's render is proof enough that it are
not different enough. Like I said before, just look at IGN the other day. One of their headline Smash Bros images used Shin's Ninten render right in the middle -- because they thought he was Ness. Just because they're ignorant about it is besides the point. They represent the average Nintendo gamer still.