Programming with this will take forever. I think, instead of making the visual cues map to one token at a time, why not make it more high-level. I dont have an idea how that is supposed to look, but it will make it a bit faster if it has visual templates for constructs like if/else, switch/case, for/loop or a function block, where you just go in and add in the comditions and operations.
Also, if you can add some kind of zoom out feature that makes some larger details smaller so you can look at the program or a subset of it from a higher vantage point.
This has the potential of being really useful.
Another thing I can think of in relation to the template stuff is to make the language really expressive and clear, since the user won't be typing most of the boilerplate except for maybe the variable names and operators. One more thing, map keyboard shortcuts to templates.
I'm also a language designer by the way. Peace. ;)
I think that being able to drag a right curly brace and a left curly brace separately is a mistake. I don't like visual language too much, but one of the advantages of visual languages is that it's impossible to have a mismatched parenthesis or brace. It's more friendly to newbies to have the correct balance of delimiters.