I think the take away from existing visual languages is that they can be quite nice but the less they mimic imperative blocks with drag and drop the better. Functional programming is a better fit.

They work well for stream processing.

They can often be more elegant in how they define and consume inputs. Many more parameters can be supported in a visually pleasing way, which cleans up parameter over loading and makes it easier to compose function block together without making Tuple types.

This could very well exist but I think a visual Lisp would be interesting.