I'm aware of the preference for 'general answers to general questions' attitude on SO, and wholeheartedly agree that questions that are focused on specific, one-time issues are not as valuable to the site. However, where an issue is potentially useful but getting to the heart of it is taking some doing, the obvious option is to migrate the discussion to chat. Once the user has a better understanding of their issue, the question can be edited to a useful form and answered succinctly for future readers.
The issue, as noted in other questions here, is that these situations most often occur with a sub 20 rep user, and so with the chat feature denied a long discussion in the comments becomes likely. I totally understand the sentiments expressed here: Add "invite user to chat" function on main site, and I don't feel that a chat session should be used to completely solve a users problem, but it would be nice if the chat could be made available while a user's issue is being made clear. And so...
The Actual Proposal
Would it be possible to enable the invite to chat feature for sub 20 rep users, based on an invite from a higher rep user who can be trusted to use the chat conversation in the correct manner and take the results back to the originating question?
The sub 20 rep user could be locked to that single chat instance, and still unable to participate in the main boards. The inviting user should have a much higher rep, somewhere in the thousands, and so would hopefully use the feature responsibly in a way that was aimed at providing a worthwhile question and answer as the result.