Do you have an example viz from another source showing the sort of parallel plot you are thinking of? I'm not sure of the use case from the example workbook but I appreciate teh work you put into building the sample. Thank you
Check out Parallel Coordinates via Pivot and LOD Expressions | Drawing with Numbers, it shows a new way to do it using Tableau's pivot feature that solves some of the display problems of prior versions. In any case, there's no way around normalizing the scales to get everything onto the same axis.