While I applaud his effort, this is why wonderful movies aren't musically scored by the director or writer - they may know what they want, but that doesn't give them the ability to create it.
When all the musicians only want to do musics that won't fit a movie, yes, a director should go on and score his own movie.
If designers want so much that programmers get their fonts from them, they should try to create something that's suitable for programming. That does not seem to be happening now.
And, yes, I quite liked it. If I hear about it again when the author releases it (why didn't he already?), I'll probably try it.
There are directors who have scored one or many of their own films, such as John Carpenter, Robert Rodriguez, and Clint Eastwood. It's true that excepting the ones who have a strong music background director-composers usually produce somewhat simpler and critically not-acclaimed scores but they also often end up working well. Look at the Halloween theme; it's a very simple melody but it somehow captured the mood of the film and people's imaginations.
I agree with your general point though, a collaboration between the "user" and "expert" will generally produce something superior; but sometimes there can even be a little bit of a liability having the other party around.
The school teacher thing is a poor example though - that's just marketing trying to make an appeal to authority. Something like if a teacher had designed a desk or chair would be better because their job gives them insight into that as opposed to say, a mail carrier.
While I applaud his effort, this is why wonderful movies aren't musically scored by the director or writer - they may know what they want, but that doesn't give them the ability to create it.
Like medicine "created by a school teacher".