7.1 Faster Interface
The interface slows down drastically when applying lots of Expressions, Code allows us to easily create complex animations and connect values. This is the highest on my list of improvements that After Effects can make.
Imagine defining one variable that you could use throughout the project. For example: n = thisLayer.name Now “n” will return the "Layer Name" of the layer on any property. This would reduce the amount of re-typing code.
7.3 Option Pick-whip
Option Pick-whip could clone the Expression itself rather than the value it returns. This solves having to update duplicate code.
Expressions are meant to be little scripts in the timeline but have taken on a more dominant role. More people are using Expressions to connect parts of their animations. Tweaking this code can be more effective using a proper Code Editor Window that has features like Colored text and Line numbers, etc.
Also note that the Code Editor could display the propertyGroup(); index number (1) this helps referring to other properties by index. Learn more about propertyGroups here.
Maybe After Effects could collaborate with an already existing code editor like Atom