I met with Bret Victor for lunch while visiting SF a few years ago and I specifically argued against visual programming languages making anyone able to program. I mean I know that some people are more inclined to think in blocks and visual metaphors (Hell most programmers draw out ideas constantly cause we do too) but any sufficient program eventually gets complicated enough that visual programming kind of breaks down unless it gets more and more abstract to make reusable components and modules that you can navigate too etc. I pushed at the time and I'm not even sure he remembers at this point but for augmenting text based programming and making what's happening more visual and real-time. Which seems to be some of the direction he's taking which is combining his great ideas in visualization with traditional text based programming environments. I was also a huge fan of Javascript as the lingua franca despite it's deficiencies because web based IDEs and examples were inherently so much more shareable than code you had to download and try (There could be ways around this such as a desktop repository of code viewer, but that's a friction point to people actually checking out demos/examples interactively ala JSBin as such.)

I'm personally loving what Kahn academy is doing that John Resig credits Bret Victor's talk on Inventing on Principle (http://vimeo.com/36579366) as a major inspiration. See article where he announces and explains their in browser interaction learning of CS course material: http://ejohn.org/blog/introducing-khan-cs/

In closing to name a view limitations of most visual programming languages: the naming problem (Most parts of your system need to be named in order to be able to talk about them), text based is stronger at this. Instantiation of reuseable code is pretty abstract to do visually. Eventually all programming gets complicated enough that text based approach really is easier to work with. Not to mention all the tools you can't leverage comparitvely to text based such as version control, REPLs, etc. I guess I think visual programming is idealized and people are spending all this time learning something that isn't as useful to know in the long term compared to traditional programming because all the important platforms have much richer support for text based programming (iOS, linux, C/C++ for games). But combining visualization of code execution is the perfect balance and would lead to basically replacing much commenting with an actual intuitive visualization of runtime complex structures/state. And definitely real time feedback of tuning /visual parameters is great. In the game industry all of this is very standard and I do feel there is a little more awe for his work than would be given by your typical graphics, art tool, or demo scene programming devs. Most game development toosl for say level editing and animation are all highly visual and real time interactive. Same goes for any serious AI dev they have debugging tools for visualizing all planning for entities communication, path planning, animation states, and more.

Anyway, just my thoughts. Still think Bret Victor is one of the most compelling thinkers in this space.