In blocking animation it is incredibly helpful to be able to change the color or shape of keys to indicate main poses, breakdowns and everything else. It HUGELY improves workflow and reduces time. I know certainly Maya and Blender have this feature (Blender example attached). I have tried to do this manually via Python also but there are no functions available.
I believe this update would be appreciated by animators more so following the improvements that have been made to the curve editor.
