People have tried this. Over and over and over. I love the idea, and I too have tried (and scrapped my effort), but it is an immensely difficult problem to tackle for a number of reasons:

- The moment you force a user to pick up the mouse, you have lost.

- It seems very compelling to augment the display with more information, but a lot of it is simply distracting, or reduce the density of relevant information that will fit on the page. There's a reason that even in most IDE's very little additional information beyond syntax highlighting have "stuck".

- Some weirdos (like me) won't touch tools that won't let me work over a dumb ssh connection and terminal when I need to, which is one of many reasons why...

- ... everything needs to have a sane textual format. Another reason is that it is essential to communicating about the code.

If you want to think about this, at least thoroughly review the long history of visual languages, as there are plenty of mistakes to repeat.