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.
This is probably one of those requests that sounds simpler to implement than they are, but it would be nice to have the option to use a scale of 0 to 1 to move through these. 0 = linear, 1 = exponential. 0 = easing in, 1 = easing out.
This would mean that the in + out option would not be available in this scenario, but that would be possible to math around in implementations. It would also bring about the option to animate the easings which would be fun!
The main purpose of this would be to neat up some nodes with separate curve modes and easings for 2d/3d/4d points which can look a bit excessive at the moment.