I think this is a good example of my original point 
Which is to say that the already known scopes of work and problem areas FDD addresses are not made clear and measurable.
I seem to read more posts about what FDD might do in the future and what new things could be explored, yet the known problem areas and scopes of work remain “too complex” and “unmeasurable”.
As a workstream lead who has great dependency on the work FDD does, I hope you all can first take inventory of the work you do today such that the domain is very clear and the KPIs measurable.