Few ideas for boosting the expression editor:
1) When writing expressions it can be hard to trace the matching brackets. Can we add some corresponding bracket colours to address this.
2) When I want to wrap an expression in brackets ([{or other symbols!}]) I have to manually add a bracket to the beginning and end of the expression. In Jupyter Notebooks (and many other softwares or IDEs), you can highlight a string, add a single bracket to it and it'll wrap the entire highlighted string with an opening and closing bracket.
3) Multi-line cursor. This is a real gem of a feature if possible.
I will add a GIF that demonstrates all three together in action:
All the best,
BS