This very much reminds me of labview (national instruments) and simulink (matlab). I've always found, with both of them, that it becomes quickly messy (i.e. spaghetti). But for some (simple) things it can be nice to visualize the data-flow.
How are function-definitions and function-calls implemented in your 'drawings'? This is very fundamental in Wolfram language, and needs to work very well to be useful. Not to mention recursion of a single functions or two functions that call each otherÂ…
Just out of curiosity, what language did you program that in? Seems already quite a bit of work!!