UML standards are being extended to make possible "executable UML" and although the average UML tool sucks, there are people realizing much of the Model Driven Dream using kit from certain vendors.
The data-flow stuff is definitely not useless: do you know how many engineers and experimental physicists use LabView? Data-flow tools are also efficient at parallel execution, thus you have people who are great at marketing and geospatial thinking who can create "Expert Systems." From a front-end application it is a simple server call to run the things they wrote to make business decisions.
Scratch is the one visual programming system everybody loves and it is worth imitating. In particular it is good for writing programs of the procedural variey.
Years ago I used a web-app construction toolkit called Tango where instead of writing code like PHP you stack up a lot of blocks like Scratch.
Tango was not that bad. It did not stay up to date with modern thinking about how to make webapps, but it was workable, people really built apps with it.