A very simple thing that I don’t think is well-understood is that there is an order of application, from black subtract to export, in any raw processing software. Sometimes operations can be combined, like CA and lens distortion correction (look at the lensfun library for that), but that’s not the norm. And, I think we all know here that order is important, put filmic in the correct place or be forever know as the person who abused scene-referred… 
My personal observation is that, once that importance is comprehended, the new darktable organization should be clearer.
FWIW…