a brush to create filled shapes for Grease Pencil

The Grease Pencil is improved in 2.8 but I really miss a feature. Something like a fill brush to paint colored areas.

If I paint with a brush using a material with a fill color it works like the lasso selection tool. This is strange especially with open shapes and sometimes buggy when the filling overlaps the outline shape in concave areas. (Not to mention semi-Transparencies)

There should be a brush that paints a shape by hatching,perhaps a bit more like the circle selection tool. Paint a fill and the outline edges will be created around after finishing the shape.

Another thing I don’t like is how erasers work with fills. - They just break them. If a hard eraser would change the outline shape similar to the fill brush I described it would work much better since the eraser would change the stroke shape.

A soft eraser should affect the opacity of the fill. I guess this can only work with textures. Perhaps a soft eraser could convert a fill to a texture automatically if one tries to erase a bit in a fill.