I think there is one "relatively simple" functionality that could be added to SO to assist in helping clarify vague questions, and that would not be experienced as "negative," or "punitive," by people (particularly newcomers to SO, or people for whom English is not their first language).
This suggestion would not "get in the way" of people who want to answer responding to questions immediately.
Let SO users of some appropriate "rep" (or any user?) suggest/invite questioners to fill out an optional on-line Form in which there are a series of check-boxes, or options from drop-down lists, or whatever UI is appropriate: somehow get their choices back into the original question in a useful, terse way.
In terms of the design and content of that optional on-line Form: well, I trust the creativity of the SO community, in which I am only a "larval" newcomer, could best envision that, and optimize it for maximum benefit.
Obvious things, for example in C#, I'd like to know (which are not revealed in many questions and which cannot be inferred from the question) are whether the question is in the context of WinForms, WPF, etc.