Currently, there are two radio buttons in the "Why should this question be closed?" dialog which are very similar, and which fail to clearly address a category of question which should be closed. The buttons in question are those labeled:
Needs details or clarity
This question should include more details and clarify the problem.
Missing context or other details
Please provide additional context, which ideally explains why the question is relevant to you and our community. Some forms of context include: background and motivation, relevant definitions, source, possible strategies, your current progress, why the question is interesting or important, etc.
The first is on the first page of the dialog, while the second is reached by first selecting the "A community specific reason" from the main dialog.
The close reason on the main dialog actually highlights two very common, but orthogonal, problems: the first is "PSQ" (problem statement question) style questions, which need more detail; the second is questions which consist of (for lack of a better word) logorrhea—the user writes their life story into the question. The community-specific reason highlighted above addresses the first, but we don't currently have a canned statement regarding the second. I would like to propose that we need a new community-specific close reason which specifically addresses clarity, particularly in cases where there is too much detail.
I will put some version of the language into a community wiki answer below, in case others want to massage the language without stepping on toes.
Some relevant meta posts: