Brush pen draw in a shape layer
Many AE users are also hand drawn animators and when you have a full set up of an character build in Ae.
Sometimes in your animation you want draw a keyframe because your set up can not do what you want.
Sometimes you want to make a build with tradionnal animation...
How it can be:
When you draw it make a shape layer with a path and you can draw another frames in the same path and made a morph between two keyframe.
You can have effect with onion skin in this layer.
It can be a really a huge new features for changing how we made animation in production.