I have no opinion on this question for Writing SE; I'm a newcomer and really haven't experienced the culture. Plus, any writing I do is strictly non-fiction, though I read lots of fiction.
However, I do participate in English Language and Usage SE, which has adopted the 3-vote close, and this response is to report on my experiences with it there. Many of these are due to peculiar circumstances of English teaching and learning worldwide, and don't necessarily apply here. But it's had a noticeable effect there.
In ELU.SE, there is no mechanism for distinguishing native English speakers from English learners, and no mechanism for distinguishing students from non-students.
Hence our biggest constituency is English learners worldwide, who usually just copy the questions from their workbooks and expect us to answer them. As often as not, those workbooks and questions are full of errors and very odd grammatical rules, which is of course the reason why the questioners can't understand them. These are a perennial pain in the ass, and we're generally happy to have them removed (or moved to English Learners SE) as fast as possible.
However, while poor English teaching and learning is a deep source of questions worldwide, in Anglophone countries (UK, US, NZ, Australia, S.Africa) the standard of English grammatical education is different, but no better. English-speaking students in English-speaking classrooms do not typically learn anything about English grammar -- rather, they learn a catechism of shibboleths, of things they may not say and ways they may not say them, all enforced by the idea that Writing is the basis of language, and pronunciation is irrelevant -- only spelling is important. Consequently, their questions are often pretty silly, too, and the sillier ones are getting swept from the table sooner by the 3-vote rule.
From my position as somebody interested in answering questions, that's all to the good. I'm not fond of repeating myself, though every teacher knows you have to.
I haven't seen any really bad effects yet (though of course I miss a lot), but our unending piles of dumb questions in ELU.SE may not have an analog here in Writing. I have noticed that it's much harder to close a dumb question in Linguistics.SE, which still needs 5, than ELU. That doesn't seem to harm things, though.