I’m sure many would appreciate them. I too am rather surprised custom curves haven’t become a thing, as they avoid the interpolation of luts.
It sounds like you are using the display referred workflow. Have you tried scene referred? Most here will use filmic, which comes with its own curve. Recently, I have taken to using filmic only as a tone mapper to control Black and White points, whilst making the curve straight. This allows one to use a custom curve in another module. I’ve been doing that either with either tone curve or tone equaliser. So is there any reason you chose the base curve module over those?
I also find it useful to Compare my custom curve to some other Presets, as there is nearly always a preset that does it better - but rarely the same preset each time. The Presets I’ve been using are the film emulation luts from rawtherapee, which are downloadable from rawpedia. That folder contains hundreds of luts. I’ve narrowed it down to about 30 favourites which produce the goods regularly. With more use I hope to narrow it down to 10 or less. But I wonder how easy it would be to extract curves from these luts and save as curve Presets?
This is a particular topic of interest for me at the moment (albeit off topic from original discussion).