I believe that questions that aren't answerable in their current form do need to be closed promptly to avoid accumulating a series of answers that guess at what the question is trying to ask and answer a series of related (or unrelated) questions that aren't, in fact what the OP is looking for. I agree with stuffestuffe that new users in particular often see closing as permanent and are scared off by it.
My suggestion, therefore, is that questions closed as NARQ show up to the user as "on hold" or something to that effect rather than "closed." The purpose of this would be to invite the OP to edit to improve the question. While this is functionally no different than closing the question, it sends a message to the OP that is more clearly "please fix this" and not "go away." Perhaps edits to a question "on hold" should automatically generate a flag to attract review whether the question is ready to be reopened.
Prompt closing is the right tool for unclear questions. I don't think we should stop doing that at all. I do think we could explain ourselves more gently to the OP so prompt closing can be taken as an invitation to dialog and not a stern "go away" message.
