Hi, Congrats on ver 5!
I'm looking for a raw processing tool that allows me to control the saturation of shadows, mids and highlights separately, or using a luminance/saturation curve. Davinci Resolve does it (http://nofilmschool.com/2015/11/simple-trick-make-your-color-grades-look-more-professional) as well as other high end colour grading tools, but no raw photo processing tools that I can find (Capture One has 3 way toning but not saturation). It seems this could be a really useful and efficient addition for correcting or adding casts in different luminance ranges as well as creating some beautiful looks, without having to use local adjustments or export to PS or GIMP.
The way I imagine it working is as a standard saturation control but effectively masked with a curve for a particular luminance range.