It will be a simple but an effective update to have MatCap shaders for the viewports. (Maybe an easy way to override the viewport with a user defined shader)
Take a look at this script.
http://cganimator.com/superclaymode-v1-1/
It will also be nice to have user defined shaders for Stylized tab and/ or parameters to control the thickness of the line and various parameters for those shaders. It will be nice to expose those shaders under Quicksilver renderer at the same time.
