We code with text because it leverages our innate language skills. Words and grammer are how we communicate naturally. Typing in words and numbers transmits an enormous amount of information very quickly, compared to e.g. manipulating graphical controls. We use diagrams for very narrow domains of information, not for general concepts.

If you've got something better in mind, let's see it. I mean, let's see exactly how it is supposed to work. The general idea has been around a long time, but nobody has produced even a design that is compelling.