Simplicity / structure in drawing

I think a key to drawing good faces for manga / comics is simplicity in execution with solid structure that is only hinted at in the final piece. That is, the forms and the structure of the elements in the drawing need to be well developed but there should be a minimalism in terms of line work in the final drawing. 

I'm thinking particularly of Samura and Tsutomu. Their is very little line work in the faces, but they have a consistency and style that carries through their work.

As opposed to having a good structure and too much line work or bad structure and minimal line work.

Perhaps I'm discovering for myself, two crucial elements to drawing comics: line work and structure. Both  need to be at a high level of skill while being developed in different directions in terms of quantity.

That is, with structure, more structure, more knowledge of form is good. Where as with the line work representing that structure, the less the better.