See Notes on Lowering the Barriers to Programming for now....
End user programming languages are generally considered to be ultimately front ends to text languages. Toys that don't easily fit this model are seen as tools to teach programming concepts so that users may ultimately move on to "real" programming languages. However, I believe that many of these toys actually represent a fundamentally different kind of programming, where the runtime for the program does not exist anywhere as code. Instead the runtime environment is a physical or virtual reality environment.
This kind of runtime is potentially more comprehensible, improving usability. It may also be better suited to representing parallel algorithms than code.
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More chatter:
Lemmings, world programming, Curlybot, Electronic Bricks, and Lego Intelli-train seem to present an alternate model. There is no loop counting down while the train approaches the smart whistle brick. There is no parser feeding an if statement a boolean when something touches the electronic brick. These things are controlled by properties and events in the world.
So while there is some code involved, it is contained, and it doesn't co-mingle with the real program, which exists in reality or in some sort of virtual reality.
That didn't come out well, but I'll work on it next week.