The fact that this was done in just 430ish lines of BF really illustrates some of BFs power that may be lost on others.
It's not the worst language if you're willing to work within the constraints and frankly, more readable than a lot of C++. My own editor (written many years ago, no meta interpreter) was 113 characters.
Also note that 430 lines is the code compliant with our bd.style: heavily commented, unambiguous, modifyable. You can always minify the code and it'll be some 1K commands, which is pretty small for a text editor.
I was waiting for the super optimising ed plugin.