I read the whole thing - delighted. More of a programming "implementer" than a "designer," I have intuited things like this before... And when I was required to learn control theory and simulink (which uses graphs), it grew deeper in me. I had a system of equations with a dozen variables (represnting a medical device and body physiology)... Some measured accurately, some interstitial guesses. I wanted to be able to transform the system around into many forms. I eventually learned Minsky, simulink and modelica, but wanted better tools.

From that experience, one thing I would consider adding to your system is physical units. I independently discovered that physics units (Ohms, inerita, etc.) can be described as a vector. The other thing that is missing is out there and would be a boon is a real-time element for design. So many of the UIs are blocky in their design, meaning you sketch for a while, then press a large, heavy compile button, and wait for your results... To counteract this frustration, I have been undertaking experiments in real-time compiling. Please contact me if you're looking or a co-conspirator! I have been conceiving and part-time developing an environment where you can model systems continuously in real-time (or faster). Each time you make a change, it runs a number of tests and in fact, your changes don't have to be "complete." The system can iterate in the direction you send it and converge to your spec.