Twenty years ago I was a researcher (Fraunhofer) on executable UML, especially on aspect oriented programming (AOP which was a thing back then, but never caught on). You could draw a boundary around some UML process flow, and attach an aspect to it. For example a security boundry, and then the code generated would automatically add a security check aspect for all flows going inside.
What we did find out, text is just better to read and understand. It's easier to refactor and much denser. We experimented with different levels to zoom in and zoom out for bigger programs but Visual programming does not scale (or didn't at least back then).
That was the premise of UML and the dream Rational was trying to sell with Rational Rose – that in the future, there would be no conventional programming languages, no software engineers, only architects, philosophers and visionaries wearing suits and ties, daydreaming and smoking pipes, who would be imbued with senses of self-importance and self-aggrandisement using Rational Rose and its visual language (UML) for system design and actually for every.single.thing., and Rational Rose would automatically generate the implementation (in an invisible intermediate conventional programming language as a byproduct). The idea was to obliterate the whole notion of programming as we know it today.
So the implementation in the intermediate programming language (C++) was not event meant to be readable to humans – by design. Rational Rose (the app), however, was too fat, too slow and (most importantly) buggy AF – to the point of the implementation it spat out nevery being able to work. And, UML did not meet the level of enthusiastic support Booch and Co wholeheartedly hoped for.
Whatever the reason was for Grady Booch's personal crusade against the programming and an attempt to replace programming with visual programming, it has failed and done so miserably. Today, the only living remnant and legacy is UML sequence diagrams, and even class diagrams are no longer seen in the wild.
You seem to have come to if from the wrong direction. The entire idea behind the Rational Process was that in the future, your architects would have to every 2 months or so come down from their conference rooms and talk to the *grasp* developers.
IBM had quite a hard time selling this idea. So they decided to push their marketing people outside of their target customers. That may be how they got to you.
What we did find out, text is just better to read and understand. It's easier to refactor and much denser. We experimented with different levels to zoom in and zoom out for bigger programs but Visual programming does not scale (or didn't at least back then).