I think Anime SE is a really good community for Anime/Manga fans to discuss their opinions about animes or mangas and anything related to them. So I think we should allow opinion-based questions and maybe add a new tag for such questions.
Stack Exchange, by its nature, is a fact-based objective Q&A site. For every question, it's expected to have a correct answer.
Opinion-based questions are well, eliciting subjective opinions, which may be true or false, depending on the readers' opinion itself. Thus, there is no correct answer, or well, all answers are correct. Because, my opinion!
Voting then also becomes a problem, because, in the end, it's a popularity vote.
Take an example from your comment
Why do people like Anime X?
- One might say that the story is good
- Another might say that the OST is good, but the story is meh
- Then someone might say that the character design and the art is unique, but the OST is so-so
So, what do we get? Good story, or not? Good OST, or not? Unique character design and art, compared to other anime?
The problem is, these opinions from their fans practically apply to all anime series. Even some people don't agree with anime critics' opinions because everyone has their own taste!
And about voting, what do the votes indicate? If I upvote (2), does it mean I agree that "the OST is good, but the story is meh"? However, my opinion is that the story and the OST is good. So, should I vote (1) and (2) instead? Or write a new
answer opinion instead? Or instead, commenting?
Comments? Oh... I can't imagine how the
Q&A opinion thread will look like, not even moderating them...
Let other anime sites that already allow user's review (and open-ended discussion, for this matter) do their best.
Anime & Manga Stack Exchange does not need to cover everything.