They really limit their own usefulness by throwing out the baby with the bathwater.
Creating a good site for discussion would be quite a bit of work, paramount to creating a different platform. I could perhaps see them expanding to that style of site and reusing the StackExchange brand in the future, but it would essentially be a separate sort of product. For now, it makes the most sense to focus on what they're already great at: Q&A sites.
These sort of questions are much better suited to places like HN and Reddit, although those also have their own problems. (Mostly, discussion tends to be short-lived: almost nobody looks at HN comments a day after they've left the front page, and Reddit isn't all that much better in that regard.)
Are they actually ill-suited to this sort of discussion though? Most of the closed discussions like this that I have seen have actually been very good. It seems like they are closing these discussions because the site wasn't designed for it, but not because the site is bad for it.
It seems to me that removing answer selection would be all that's necessary to create a place for discussion.
I suspect the real root of the issue here is that there's a lot of karma points attached to the green checkmark, so that the gamification system effectively punishes people for not checking one regardless of whether it's really appropriate to do so. And someone noticed that, and got as far as realizing that the problem came down to the gamification system was slightly out of phase with where users were actually finding value in the site.
But then they had a brain fart and decided the best way to fix this wasn't to tweak the gamification system to fit humanity, but instead to try and tweak humanity to fit the gamification system.
That gets said a lot, but the truth of the matter is that it works just fine for this kind of thing, too. Stellar case in point: The linked article. It even has (or at least had) features which are specifically designed to support this kind of scenario. Remember the Community Wiki feature?
The site is absolutely littered with great resources on topics which a small number of the site's moderators have deemed too subjective to be of value but which the site's users have upvoted into the stratosphere or provided extremely useful, thoughtful answers which other users proceeded to upvote into the stratosphere. Oftentimes they were around since near the site's beginning, enough time to become top Google results which are often linked by blogs, and generally done quite well for themselves - all a testament to how excellent a job Stack Overflow's format does at producing extremely high-quality content on these topics. Only to get closed anyway within the past year or two, in the service of trying to force this bizarre reality-deaf Pronouncement from Above that, regardless of what anyone's actual experience may be, you are mistaken and Stack Overflow can't actually do that.
In summary: If the people who run Stack Overflow were in charge of Apple, there would be a ban on music/podcast player apps on the iPad justified by nothing firmer than condescending lectures about how Steve Jobs prefers audio players that fit in his pocket and has therefore pronounced that the iPad is fundamentally unsuited to the consumption of audio content.
As far as I can tell, the only practical consequences of having them as two separate sites are that you have to set up different user accounts to use them, and the SE.com is less discoverable because search results depend on what subsite you search on. Not exactly a great win for usability.
Having separate sites for completely separate topics (like most the others on SE) makes all the sense in the world. But sticking a Berlin wall between the categories of "programming questions" and "other programming questions" is just goofy.
To my mind, the original once-sentence statement of how P.SE is different from SO (Paraphrased, "SO is for when you're sitting at the keyboard, P.SE is for when you're standing at the whiteboard.") makes it clear that the idea was fuzzily-conceived from the get-go. And it only got more muddled when the maintainers of the site, which had originally been specifically envisioned as a place for subjective discussion as per the very first sentence of the (original) site FAQ,* came out with a decision that it was absolutely not a place for subjective discussion, no how no way.
*Those with long memories will catch me out by pointing out that the very next paragraph of the original FAQ started by making a sudden one hundred eighty degree turn and specifically admonishing people to not ask subjective questions. I must concede that this is absolutely true. But I would counter by saying this fact doesn't make P.SE look any more well-conceived.
It seems the right kind of place to me.
2. http://www.reddit.com/r/programming/ is a terrific discussion forum for for all programming-related topics.
I would agree that there's a niche for a high-quality discussion forum that is currently not filled. Reddit has, well, "redditors", and has entirely too much NSFW style content. A more buttoned-down site would be nice.
I imagine it providing a way for people to pose potential problems/questions, and either letting users post their suggestion/opinion of how the problem should be solved. Rosetta Code limits itself to programming problems, but this hypothetical site could allow more general questions/challenges as well.
Building a community around open-ended questions like this is next to difficult. SE was able to counter this because of the nature of the allowed questions. A website with the premise of "ask programming questions that do not have a specific answer" lacks the specificity to cultivate a community that is connected enough to be lively (based on my small amount of experience with forum management).
SE is in a good position to attempt such a thing because the community already exists.
However, it may still face issues with liveliness.
It may be a better idea to just allow these sorts of questions with a specific tag (and visual indicator on question links).
Why not have a discussions.#{sub_domain}.stackexchange.com ?
Questions like this one would be moved there and you would need a certain level of karma to participate. Somewhat like HN
Edit: Did it http://meta.stackoverflow.com/questions/161305/why-not-have-...