Definitely should be able to put functions in the horizontal space, use colors as part of the syntax, use Unicode symbols where it is warranted.
I would go farther and say that we should have at least some ability to edit things in a non-serialized way, like a WYSIWYG math formula for example.
I hope people will also explore structural program editing. https://en.m.wikipedia.org/wiki/Structure_editor
Almost forgot, one more crazy idea: switch to larger instantly reconfigurable touchscreen keyboards to allow more symbols to be entered easily.