The problem in this space isn't a choice of content over form.  I'm strongly in favor of relaxed structural rules in written communication.

p6 is a fine successful example of content over form: no restrictions honored that anyone might be able to identify, but the communication occurs, eh?  I never have any difficulty figuring out what he's trying to say.

The difficulty facing high school students is that very few of them have ever written with the sincere goal of communicating. They write because they are ordered to.  The combination of lack of form and lack of interest shows up as garbage text, and now we're at an educational crossroads.  We can focus on the lack of form; it's not a matter of opinion, and the historic analysis was that this was what the student was there to learn. Or we can aim higher, trying to get to communication without worrying about form.

Plenty of great writers distain standard form, which is what tempts aiming high.  But it turns out to be dangerous territory.  Many students gradutated with neither form nor communication, and were totally unprepared for more advanced work.  As one progresses through college and then grad school (not to mention real life), the requirement for success increasingly involves the ability to communicate in writing.  And for many, the historic way, a focus on form in high school, did in fact prepare them for this future requirement even if their desire and ability to communicate was avoiding intense attention.  Once motivated, they found themselves with a bit of a foundation to branch out from.

Most (not all, of course) students without such a foundation found their life considerably handicapped, and many never have overcome their belief that "I just can't write".

Actually, my approach to presenting a point is pretty structured. For instance, that last sentance was rewritten three times because the word that leapt to mind..."rhetoric" instead of "presenting a point"...left a nasty aftertaste. And I try to use sensual reality in my metaphors. That way at least when I leap to a conclusion I know I did it.

"rhetoric" is a perfectly respectable word which has fallen in with a bad crowd.

That aftertaste is the same ill informed taste exploited by those who claim evolution is "just a theory", which basically explains that they don't understand the difference between a theory and a conjecture.

Actually, my approach to presenting a point is pretty structured.

That I observed, and admired.  There's a real distinction between structured and constrained.  Without structure, it's hard to follow. Without constraint, one may paint the rhetorical canvas with colors outside the conventional gamut.

You inspired a post at my other blog on the N-Net. 

Wikipedia opens its article on rhetoric like this:

Rhetoric...is one of the three original liberal arts or trivium (the other members are dialectic and grammar). While it has meant many different things during its 2500-year history, it is generally described today as the art of persuasion through language. Rhetoric can describe a persuasive way in which one relates a theme or idea in an effort to convince.

The key concept to extract from this is "it has meant many different things during its 2500-year history." If a word has meant many things (and what word hasn't) you have to recognize it has no inherent meaning at all...that a word, any word,means "that which I indicate by using the word." The definition of any useful term will inevitably expand, but you have to wonder how rhetoric fell from Aristotle's the power to observe the persuasiveness of which any particular matter admits to the current understanding of the word:

1. using language effectively to please or persuade
2. grandiosity: high flown style; excessive use of verbal ornamentation
3. palaver: loud and confused and empty talk; "mere rhetoric"
4. study of the technique and rules for using language effectively (especially in public speaking)

When I came on board I understood rhetoric to be the art of ethical persuasion, or persuasion by ethical means. The "ethical" part has fallen off the definition...as we speak, rhetoric means "the art of persuasion." Unfortunately, rhetoric is the primary tool of politics. I watched as "ethical persuasion" passed though "persuasion through ethical argument" and "persuasion by moral argument," to "persuasion by invoking moral repugnance toward the alternative." This type of rhetoric is why accusing someone of making "political arguments" is somewhat damning (even though it always seems to be a politician making the accusation...).

so i'm going to dig into this one: rhetoric, or effective communication, relies upon three tropes:  logos, ethos, and pathos.  Aristotle defines them as language used in argument [logos], character of the speaker [ethos], and emotional appeal [pathos].  logos, or logic, is given prominence because many like to argue that it is objective and empirical, while the other two tropes rely upon an audience's response to the speaker.  The fun part of rhetoric to me is that reality is socially constructed, so a logical appeal is only logical if the audience shares the speaker's worldview.  e.g., white people have trouble understanding why blacks distrust police because whites are not often subjected to the arbitrary and demeaning police practices that blacks endure.

so...let's be clear.  a 'fact' is contextual; it is only effective (and logical) if it consistently agrees with the epistemology of the social group it is argued among.   

sidebar:  this is why it doesn't really help to use literature to teach argumentative writing.  like DW points out, most great writers are idiosyncratic with regard to writing style.  

however, as a former English instructor, i used african-american literature and critical race theory to teach argumentative writing.  why?  because it forced students to work hard to clearly articulate their positions regarding race and racism and coincidentally, they had to learn how to argue consistently.  some of those papers SUCKED because the kids couldn't sufficiently disengage, but that's why they paid me, right?  teaching argument using race was effective for me because i could point to real-world examples to dislodge fallacious thinking.  now, i will admit - when i didn't have any minority students (this was at Carnegie Mellon, so you know this happened more than once) the class was more difficult to teach cuz i had to use my own experiences to debunk da bullshit the kids spewed.

so content is necessary to shape form - but critical thinking (meaning the ability to question status quo as handed down by institution/custom/law) is just as important.   

Have you noticed the discourse in the Black communities uses logos as evidence of ethos?

That's not quite right.