Rename BitmapRenderer to ImperativeRenderer and expand feature set so it can be used to simulate imperative use of traditional GraphicsDevice/SpriteBatch.
Add basic line/rectangle rendering to ImperativeRenderer.
Add a built in material cache to DefaultMaterialSet that lets you efficiently get versions of existing materials with blend/rasterizer/depth states set.
Add a ModelView matrix along with the Projection matrix to make more complex camera control possible.
Extract the camera related properties of DefaultMaterialSet into a new ViewTransform type that can be manipulated easier.
Add a ApplyViewTransform method to DefaultMaterialSet so you can temporarily change the view transform without mutating the field.
Add convenience statics for constructing a ViewTransform.
Add a Bounds constructor that accepts a Rectangle.