Also, "visual languages" even when restricted to very specific domains (think of DSP blocks, a tried&tested domain where visual languages are abundantly abused)

Also, "visual languages" even when restricted to very specific domains (think of DSP blocks, a tried&tested domain where visual languages are abundantly abused) tend to get very messy already when only very simple logic is involved. I wouldn't classify simple IFS systems in recursive painting programs to be "programming" at all. Where's branching, for instance?