This has to be a FR somewhere, part of many discussions, but I couldn't find the focused idea, so here. I did see the keyframe FR, but this one is more basic, also purposely less complex than the QC timeline with multiple timelines and all that. Most basic graph module that allows a user to add points to it, normalized/mapped to [0,1] along x and y axes. Personally, I'd be fine with linear interpolation and no spline handles. And leave the graph exposed in the editor. The only "extra power" feature that might be cool to consider is ability to group multiple into a subcomp/single GUI. Or not -- something, anything!
Side note: I live in the SF Bay Area. I know a coder who worked at Pixar, talking about a huge breakthrough for animation at the time -- it was this idea -- a simple spline graph animators could use to quickly animate/articulate characters.