I suppose that it's only really helpful in a rather limited count of usage cased, some of which were stated here.
OTOH, I do agree that (e.g.) providing a flexible internal positioning / routing of the fader within the FX chain of a track would be perfectly in line with the versatility Reaper usually provides. E.g. similar to ->
https://forum.cockos.com/showpost.ph...44&postcount=1 (Thanks DarkStar). A simple "Fader" pseudo-plugin in the FX-Chain list would suffice as the GUI for this.
-Michael