You may be missing the forest for the tree. I am not talking about the filter graph in isolation. I am talking about specifying all command line arguments (inputs, seeking, outputs, filters, codec options) etc. in a structured way. Filters would only be a part of that.

I think this might make use of ffmpeg less daunting than people attempting to battle a single-line shell input, ordering-sensitive parameters and escaping.

Well, maybe it's redundant, there already is vaporsynth after all.