I understand what you are saying conceptually, and I understand the desire that a place you spend time with have more "worthy" content. It's the frustration of flipping through a magazine and realizing there's only one good article and the rest is total fluff.
But I'm questioning the logistics and reality of what you're talking about. How is more content in opening remarks being suggested, and by whom?
And if a sub-forum is created where the expectation is that discussion is deeper, then I think that does require moderation or at the very least creates a situation where people are being policed regarding the quality/quantity of what they are writing.
Norms, conventions, and expectations are created by a community. On a forum like this, you then also have the other layer of moderators who enforce official policies. But how people use a site like this varies widely by what they want to get out of it. A fundamental problem you're running into is that group norms can only exist when goals are aligned, and the goals of people using this site are not totally aligned in terms of what they want out of posting here. Some people might just want to have a place where they can learn about movies they haven't heard of, create a log of what they've seen, get some basic social interaction, etc.
So, again, the best way to shape the behavior of other people and the overall nature of a place is to support the behaviors you appreciate and ignore the ones you don't. And, more broadly, accept that some people may not use a space in a way that you like. I post on a semi-private journal thing, and there's one guy who uses it to give extremely detailed accounts of his fights in Smash Bros tournaments and I kind of hate it, but whatever. Who am I to say how he uses his page?
While I continue to be surprised by your strong opposition to the basic best netiquette I'm suggesting either be suggested or enshrined in a sub-forum, I also continue to appreciate your ongoing engagement with the topic.
Can I ask if you have a sense of why you so strongly oppose what I'm proposing? I don't ask in an effort to mount some greater defense or to make fun, but just out of my ongoing surprise. Do you work in preservation, and thus strongly object to alteration? I'm being serious and not making light btw.
I appreciate your magazine analogy (do those still exist?), but feel the atmosphere of a social media site is more immersive, and that shallow distraction is always happy to overwhelm all else. A magazine can be more easily ignored as one of many, but not an environment of discussion which may fall prey to superficiality and distraction.
Logistics and reality are not complicated or dire. I'm suggesting a suggestion or a sub-forum from which topics could be moved (at worst) into genpop if the basic proposed netiquette is not observed.
No proposal of content quality has been presented, nor any policing thereof. I truly have no idea where these concerns are coming from.
I'm just asking about basic best netiquette being suggested or enshrined subforumally.
As in "I read this book about Orson Welles. It says he wasn't that great, and that Manky was the real genius behind Kane, and Jedediah (aka Manky) the only truly compelling character. Manky was my uncle, but even I disagree that he was a genius, though of course I am. Here's a link. What do you think?"
That took me about a minute to write, and lays out the topic, provides a link, and also gives a number of options in reply. ("Tell us more about Uncle Manky!" "Did he end up like Jedediah?" "I agree that Kane is not that great, and here's why.")
It's astonishingly uncomplicated, and I don't see a downside to suggesting or enshrining a few sentences to lay out the what and why. I only see an upside.
As far as "best ways of shaping the behavior of other people" goes, I'm not about that, and don't know where such a social engineering perspective comes from or why it's being erroneously applied to my very simple suggestions.
I'm suggesting what I'm suggesting, no more and no less.
I look forward to better understanding your resistance, and hope I've clarified what I'm suggesting, how it might work, and allayed your concerns about policing quality and "shaping the behavior of others."