I haven't paid attention recently, but on the topic of closing questions with useful answers, I'll repeat some of what I wrote on another meta question.
If you're working the close review queue, please check whether the question has good answers. If there are good answers, prioritize editing over closing, even if that means putting words in the asker's mouth. If there aren't any good answers and the question can't be saved without a drastic edit then the question should be closed.
Ideally, closure (apart from duplicates) should be a temporary state. A question should either be open or deleted. If a question is closed, it means that we aren't confident that we can provide quality answers, so we shouldn't expose those answers to the world. And a question that has no answers and no means to add one is not useful either.
So if a question has a useful answer which is on-topic for the site, but the question itself is not fit for the site, then please edit the question to match the answer. In a bit more detail:
- If the question is off-topic then it's probably not fit for the site. Even if an off-topic question gets a good answer, this site isn't a good place for it because voters on this site can't be expected to be good judges of off-topic answers.
- If the question is too broad or primarily opinion-based but someone managed to write a good answer, this means that the question isn't so broad and opinion-based. The question may need to be edited to be more focused or less subjective, but the proof of the pudding is in the answering. In particular, having a comprehensive answer disproves “too broad”.
- If the question is unclear but someone managed to write a useful but perhaps partial answer, then the question should be edited to match this answer.
- The problematic case is when there are multiple good answers that interpret the question is different ways. In this case the thread is usually not salvageable (this is why it's best to close unclear questions as quickly as possible), but it may be useful to preserve the answers by copying them to two or more new (or old) questions.
Note that accepted answer isn't synonymous with useful answer. Sometimes askers accept the first answer even if it's completely broken. And an answer can be accepted, but trivial and therefore not useful (e.g. if the question is essentially an RTFM case). Use your own judgement.