Although it sounded like a really cool idea, it didn't take off. Seems text is best (maybe because it supports incompatible hierarchies better).
Think about algorithm that switches values by using temporary variable for example. By looking at text, it's pretty simple to construct the flow follow the values traveling from one variable to other. But if you put it in 2D graphical interface, it becomes very problematic and hard to follow. I would imagine it would be easier if there was like a movie where value would move from one box symbolizing variable to other. But that would make it difficult to edit.
Another way would be to visually represent only change, but then it would be same as textual representation, only more redundant.
The debugger actually displays what I call a folded lattice, meaning that execution starts at the top and goes down, so representing what your talking about would simply look like ">" with lines. It would need some representation of data flow, however, which it currently doesn't have.
> Although it sounded like a really cool idea, it didn't take off.
That could have been because it was bought by Boreland, who had a history of 'not succeeding' with projects, whose focus was elsewhere, who lost key staff at an important point, and then were bought out and mismanaged from there forward?
Delphi didn't have to die the death it has.
http://www.borland.com/Products/Requirements-Management/Toge...
Both text and visual programming languages are simple representations of the structure of your program - what we normally call an AST. Neither is more 'true' than the other, and things in the text that don't match the structure are syntax errors.