I suppose that's fine. I wonder though, does this need to be specific to DXIL? If this is useful, I don't think there's a reason we couldn't support dumping disassembly for shaders compiled by d3dcompiler or vkd3d-shader as well?
It's especially useful for DXIL because it's under development. Maybe that could apply to d3dbc too, but I don't think plumbing a shader dump for other binaries would be simple enough to be part of this MR.