Interpolated Anchor Move
Similar to a font developing tool, many lettering illustrations involve maintaining the stress of a curve while moving anchors. So with this tool, you'd be able to move an anchor point and the curve handles adjacent to the anchor would move proportionally to make the curve look similar despite the anchor moving. This could be a global setting that is enabled in preferences.
Here's a better breakdown of how the feature could behave:
Reminds me of genius points in FontLab a bit: https://www.youtube.com/watch?v=Cj8GQiDnyq8
I love both things!