Very cool! I wish there were something like this for working adult programmers, a general purpose structured editor for programming languages. When I program the intentions I form are in the first instance semantic (define a function here, check a condition there). Why shouldn't I just directly communicate my semantic intentions to the editor? Why do I have to first serialize my intentions into a string for the editor to then parse, in a error-prone process which introduces the possibility of silly syntactic errors like typos, mismatched brackets, operator precedence errors etc, rather than just semantic incorrectness?
Such an editor wouldn't necessarily have to be keyboard unfriendly any more than Excel is keyboard unfriendly. I guess it could also work something like input method editors for East Asian languages where you type into a "composition window" and make selections from a "candidate window" for insertion.