Perhaps I'm a little unique, but it took me a little while to understand why subjective but relevant questions were not acceptable on Stack Overflow. (Here is the object lesson: Questions about performance versus code based solutions)
If the guidelines were updated to state these three points clearly, I think it would prevent a lot of subjective question asking on Stack Overflow, and raise awareness for Programmers:
Questions that are not answerable — discussions, debates, opinions — should be closed as subjective. It seems simple enough: Fact good; opinion and discussion bad.
Why? Eventually the experts (i.e. people who are teaching you stuff) get drowned out and you are left with an experience that looks more like the magazine rack at a grocery store than a book shelf at Harvard. (— Robert Scoble)
Subjective questions associated with software development best practices, experiences, and behaviors are not bad. We simply choose to forego those subjective discussions. That is what Programmers is for.
It may also encourage moderators to move questions to Programmers rather than closing them down.