> But I can still have a syntax error in my condition, so on what dimensions is this a net improvement vs just... typing the code?

To me this is a massive win. Structural editing solves so many problems we face as coders. Imagine not being able to save a file with invalid syntax! Imagine if changes were defined in structural or semantic terms rather than through text! The man-hours saved are mind-boggling to even consider.

Anyway intellij + java is already pretty close to this and java syntax is certainly not LESS ugly of an interface. I really just want my editor to not allow persisting anything but a coherent program....