Regarding your 4 examples: /r/NoStupidQuestions/, /r/AskHistorians/, /r/legaladvice/, /r/personalfinance/
I see why those 4 subreddits influence your thinking in how StackOverflow should work so it seems like it could adopt the same (social) mechanisms and it would only improve the site and not degrade it.
However, notice that there is no reddit.com/r/ProgrammersAskAnyQuestion/ comparable subreddit that has more traffic and/or better answers than StackOverflow even though Reddit is older (2005) than StackOverflow (2008). Why is that?
Here's my pet theory on why I think technical programmers' Q&A won't have the same dynamics as your 4 example sites based on observations of programmers asking questions for decades on USENET, Experts-Exchange, etc:
- the questions on the 4 non-tech sites you mention are often "entertainment" in and of themselves. Whether it's the compelling drama of a girlfriend asking LegalAdvice about a boyfriend emptying her bank account or somebody on AskHistorians asking about Hitler (for the 100th time), the tolerance for dupes or silly questions is much more relaxed.
- In contrast, programmers have less patience for answering someone else's "homework questions", or doing free consulting work for incompetent developers, or encountering poorly researched questions, etc. Programmers (in general) definitely have more of a smartass "lmgtfy"[0] type of defense against people wasting their time on a question forum. Yes, developers do want to help but they also have a lower threshold for annoying questions than the 4 sites you listed. (If you haven't read through the 2 meta stackexchange threads I cited in my comment you replied to, please do so to get a glimpse of this collective psychology. Also a recent 3rd thread to read to understand how some SO veterans feel.[1])
- Since a tech question like "What's the regex to extract an email address?" doesn't have the same entertainment value as "Do sighted people really look at the toilet paper after they wipe?"[2] ... the programmers volunteering their efforts don't want to see that duplicate regex question 10000 times.
I might be wrong with my analysis. Perhaps somebody can start a new subreddit dedicated to answering any programmers questions. Specifically advertise the subreddit as having no moderation, no deletion of dupe questions, no closing of questions, no downvote buttons[3] to prevent anyone's feelings from getting hurt, etc. Basically, take all the social dynamic complaints about SO and make that subreddit do the opposite. We can then see if it attracts questioners (and good answers) like your 4 example subreddits.
(I'm serious about that subreddit suggestion; it would be a fascinating experiment.)
[0] https://www.urbandictionary.com/define.php?term=lmgtfy
[1] https://meta.stackoverflow.com/questions/386584/why-is-the-p...
[2] https://old.reddit.com/r/NoStupidQuestions/comments/cxurmr/d...
[3] https://old.reddit.com/r/OutOfTheLoop/comments/4ir1qg/why_ha...