I would like to have an option to 'weather' an object.
I'm not sure if I would want to apply the effect to the whole model (for simple, quick one-click application), only certain objects/components/groups or only individual textures (for maximum in-depth control);
- edges showing wear/erosion
- rust/water streaks down walls
- splatter/creep up walls
- scratches and blemishes to surfaces (this can currently be achieved with a 'gloss' mask and/or a scratch bump, but that would need to be incorporated into the material's own surface - this would be an over-lay that is independent of the material it's applied to.)