In an ideal SE, only those with a certain number of points in a given tag should be able to nominate questions using that tag, for closure, as it seems that some pretty good questions with pretty good and clear answers can get closed if the closers' assumption is that they're not answerable.
Ignoring the systematic issues this sort of idea would bring to SE, I'd argue that the problem you present probably doesn't exist.
Most of us have the capacity to evaluate a question's quality at a high enough level to make a close vote decision regardless of the specific topic contained within the question itself.
If a subject matter expert thinks they have an answer to a question and the question should remain open while a majority of other voters believe the question is off topic and doesn't belong then I'd be willing to bet that while the subject matter expert has a really good answer, it doesn't mean the question itself isn't off topic.
Off topic questions are straight up off topic. Good answers don't turn off topic questions into on topic questions.
A lot of off topic questions around getting started and what's best comes down to uneducated users not knowing how to ask the right questions to get the answers they're looking for. A subject matter expert who really wants to answer an off topic question should leverage their domain knowledge to propose a high quality, possibly very transformative edit to the off topic question so that it fits within the mission of SE. Hopefully OP and other close voters / editors can see that the goal of the original question remains in tact while greatly improving the question to the point where the edit can be accepted and the the question ultimately can be reopened.
I won't say there aren't edge cases and what you're saying is 100% false. It's entirely possible there are edge cases. Those specific edge cases could be handled in chat or in meta to work out the specifics of those scenarios as disagreements come up. Site wide changes for edge cases is not a good idea.
Another idea is perhaps there should be a minimum time before closure can take place? This at least offers users (not just the OP) time to edit the question and make it reasonable.
This is simply counterproductive as it keeps low quality content around longer. Additionally, in general there is no motivation to make drastic edits to questions until they've already been closed.
Closing a question is not personal nor is it a punishment. It's a tool. It's a tool keep the quality of content high as well as to get people to think about what they're asking so that people can actually ask high quality questions. Editing is an option for a reason. Questions do get reopened when properly edited.