I recently posted Show that a metric space has uncountably many disjoint dense subsets if every ball is uncountable. and it quickly got up-votes, and then an answer with gaps was posted which got one up-vote. Thus the question wouldn't show up in unanswered questions searches. But the answer posted still seems to potentially have gaps even after editing, and still only has one up-vote, and so imo ideally the question should still show up in some form of unanswered question searches. Has there been any discussion on creating a "smart" ranker of questions for searching which simultaneously ranks according to time since question was posted (lower is better), number of up-votes for question (higher is better), and number of up-votes for the best current answer (lower is better)? This may attract attention of users who know a good answer to a popular question that has only received one iffy answer with one up-vote.
If you come up with a function that adequately combines the parameters you mentioned, the next step would be to head over to Data Explorer and code it into an SQL query. This is the easy part.
The hard part would be to get someone to actually use that query (or an equivalent feature of the search interface, in the unlikely event it gets implemented). People looking for questions to answer have $>28500$ question with no upvoted answers to choose from, many of which have no answer at all. The idea of looking through additional thousands of questions with low-voted answers (most of which will be correct answers that are underappreciated) is hardly appealing.