I feel there should be a media type associated with the Visual Artist

The media type (Sculpture, Photography, Painting, etc.) associated with the Visual Artist as you described is captured by the Visual Art Form type. Currently the schema has it set up as a property of Artwork instead of Artist, i.e. "Saint Andrew and Saint Thomas" by Bernini is of form Painting, whereas his "Apollo and Daphne" is of form Sculpture.

We could add Visual Art Form to the Artist type in addition to Visual Artwork. We thought art form would be more precisely modeled as a property of individual artworks, but your suggestion has advantages as well. Note, though, that most artists did not stick with one medium, and most would have more than three art forms you may not identify the artists with. Even Rodin did oil paintings, watercolors, and drawings in charcoal, and Man Ray did illustrations, drawings and paintings earlier in his career.

Let me try it on sandbox to see what the new schema would look like.

Looks good to me. May also want to link back from Art Form to Artist, in the same way we're linking back to art works.

I've promoted the schema change to production; you should see Art Form under Artist, and the reverse link as well.

But what about those that paint on something other than canvas? I've got an artist who paints eggs.