Well, actually even your question was asked before (the way I read it, anyway). The tag specific-question seems to be the focal point for the matter.
Your particular example is different, and I have to agree with @SYS_V's comment:
It could be argued that the radare2 question is more about features of a specific tool/product and less about a reverse engineering problem or concept
That said, it doesn't invalidate your other points.
What we should keep in mind, though, and that goes with a statement I made here (emphasis added):
Furthermore I think that for a Q&A site the relevance for the reader (and future internauts) needs to be considered as the prime aspect when decisions are made what to allow and what not.
... and I think I find that echoed in this statement from your question (emphasis mine):
In my opinion, even though many of these questions may remain unanswered, answers to questions like these are especially valuable.
I have to agree. As reverse engineers ("reversers") we often struggle to find the pieces of huge puzzle. I have often found myself using the smallest shreds of information I could find to "get to the next level" when reverse engineering a target. Be it information about a very similar target, be it clues about an instruction set, be it clues about that library I've never heard about before. Reverse engineering is in no small part the aspect of researching a topic, as an intrinsic part of the craft.
These questions are very specific. But they don't seem to fall into the don't-ask category, although the effort/understanding isn't always obvious.
Given how narrowly scoped this site already is, we should not always jump at the first chance of closing a question as too specific. Instead we should aim to create value for future internauts by guiding the inquirer (the person asking the question) to scope their question in a way that will encourage answers valuable to others. If the inquirer decides to ignore these efforts from the community, we can still go ahead and close such questions.
Questions such as this one should still be considered off-topic, though. They don't show the effort and are homework-like "I would like to RE this, could your do it for me" style questions.
And as a side-note: I find the notion of Real Questions Have Answers ambivalent. It's true that real questions have some kind of answer. What's not true is that a question in a very specialized fields with comparably low numbers of experts (when compared to, say, developers) which doesn't have an answer yet, is a bad question.
The distinction here being that while answers exist for real/good questions, it's by no means certain that these answers exist here and now on this Q&A site.
I remember many a case where years after initially dealing with a target, I return to it - or a newer version of it - and happen to crack the puzzle this time. Whenever I have asked a question before and remember/find that, I'll go to the effort of answering it to leave a "memo" to myself and others.
Similarly I've found myself answering questions that were years old, because there weren't any answers or the answers were outright dodging the question.