I'm working on a very similar experimental editor for Clojure/lisp and my intention is to make it vi-like - navigate and perform the edits with the keyboard.
Some other ideas I'm experimenting with:
Customisable icons or even specific shapes for functions.
For example the function "show loading screen" can be represented as the actual visual screenshot of the loading screen.
The idea is to get rid of most of the syntax and leave only the user-defined names.
In 'interactive' mode, each form (block) can be executed and arguments can be entered right inside it.
Each function block could have a 'back side', where all the meta data about the function resides, like documentation and unit tests.
So visual programming is a new hot topic and there's a lot of stuff to explore in this area.