I never understood English grammar until I took HS latin. I made good grades - I just didn't get it. After latin, though, I realized, for example, the difference between phrases and clauses. I understood that while grammar rules are somewhat arbitrary, that it was good to agree on some things (so as not to have the romans sneaking up on their own rears).
I think some of the criticisms are off base. Of course the author of this article believes that content is important. Of course he believes that one needs both form and content to communicate. If there is no content, what is the use of communicating? But it's like Mrs Schlinker told us - she didn't care what we had to say, but only that we said it well.
What essayist has done is taken something like sentence tree parsing and gone to the next level with it. He has abstracted the problem of communication in the same way that a class in HS algebra abstracts the problems of mathematics.
You learn the forms and develop some comprehension of the underlying mechanisms in class and later, when you have to solve real problems, you're on surer footing. You don't have to think about how to set up a set of equations in 3 variables or 5 or even 10. You have the basics down and not only that, you are sufficiently comfortable that you can skip steps, combine methodologies, perhaps even develop new ones. You can use your toolbox of methods and formulae with the same creativity that some guitar players use with the fixed set of chords they have learnt.
The only criticism that I might level against this approach is that it might be too abstract for some students. But I don't think every course needs to be geared for the success of the lowest common denominator.
