It seems like this thread has digressed...
I'm not here to offer a solution, but I'm seeking a similar work around.
So, by way of example, I'm contributing a real world example of why it would be useful to be able to affect the surface pattern or cut pattern of an element. (Not via a Fill Hatch Region)
Architectural problem:
I need to convey the extents of the demolition of a roofing membrane in plan and the insulation below. Membranes in general do not have a surface pattern. So, the phasing graphic override has no affect. I added a surface pattern using a custom pattern I created with dashed lines to denote demolition. However, the line weight is automatically set to 1 and can not be modified. So, it doesn't read bold enough like the usually heavy weight dashed lines used to indicate demolition. Using a Filled Region gives me the ability to affect the light weight but the Fill Region interferes with Keynote tags. The keynotes lose their host because the Filled region gets in the way.
I think it would be helpful if, in the PAT file where we create fill patterns, Revit could include another parameter for light weight and/or line style. Then, pattern creation may take on a two step process where first you defined the line style or reference an existing one, then indicate the rest of the pattern geometry using that line style. It might even be cool if you could mix line styles instead of having to define them each time within the pattern definition - i.e. Dashed weight 1, solid weight 3, dashed weight 1... (with the usually offset and origin beginnings).
...just trying to emphasize why having such a tool would be necessary.