> English is infinitely more scalable than any programming language, and the brain is far more capable of understanding than a computer. So comparing the two is unfair to say the least.IMHO programming a large system shouldn't be all that different from writing an encyclopedia, or rather a math textbook; the same combination of informal explanation and formal demonstrations could be the shape that "visual" programs could take. Literate programming is written in English, and it provides much of the same advantages of the encyclopedia or technical book. Systems like IPython / Jupyter work in that direction, and they belong in the family of visual programming (although they use "classic" languages for the formal part, nothing stops them from also including graphical models as part of the code specification).
Programming languages should be made for human consumption, and one of the promises of visual languages is that they use secondary notation to convey the meaning of the program, so that parts that are not visible to the compiler are still relevant.
I believe that programming environments should converge towards a hybrid of programming, using the best representation for each concept - like text (to represent abstract concepts), diagrams (to represent more physical properties - time, data flows, and dependencies between modules), and raw text for the human-readable comments that explain how everything is tied together. If you build a programming environment like that, my comparison is not unfair at all.
>Live programming for instance requires context and re-running of code on every edit (and we could be talking millions of lines of code that need to execute), re-reading of data files, re-running of prior user input and so on. There's a reason it is only implemented for small systems (read, useless practically).
Modern IDEs are capable of doing a lot of that when in debug mode, I see no reason why having a language with a graphical syntax should make any difference - it just places a little more weight on the parser and graphic card.