We don't have a lingua franca for diagrams like we do for text files.*

What is UML, then? If you feel stuck with this then maybe you need to look outside the text = code bubble and get some input on tool design from other sources. I agree that text is a convenient serialization and storage format, but it's a terrible design and analysis medium.

I mean, consider CSound, which is a tool for writing music with computers that has a venerable heritage going back to the 1970s. You have one set of code for defining the charactersistics of the sound, and another for defining the characteristic of the ntoes you play with those sounds: http://www.csounds.com/man/qr/score.htm and http://www.csounds.com/manual/html/index.html

CSound is a moderately good teaching tool, and given its heritage it's an impressive piece of technology. But nobody writes music in Csound except a few computer music professors and the students in their departments that have to do as part of their assignments, and 99% of music composed in CSound is a) dreadful and b) could have been done much faster on either a modular synthesizer or with Max/MSP. Electronic musicians feel the same way about CSound that you as a programmer would feel about an elderly relative that keeps talking about when everything was done with vacuum tubes and toggle switches...you respect it but it seems laughably primitive and has nothing to do with solving actual problems. The very few people that need low-level control on specific hardware platforms work in C or assembler.

I think this is pretty relevant here because one of Bret Victor's more impressive achievements is having written some very impressive operating software for a series of synthesizers from Alesis. I'd be pretty astonished if he even considered CSound for the task.