Some months ago I had posted a question in the line of "Which mathematical papers should be translated?" which soon after got voted to close because it was deemed to depend on opinion. I'm not trying to get the question reopened (I knew it would be dead after in some replies it was tried to render the question ridiculous); I rather would like to know, whether "opinion based" questions couldn't be acceptable after all.
My motivation for this questions is, that there are different meanings of the term opinion and I think only some are inappropriate for MO, namely those that are aimed at confrontation, betting, superstition or discrimination. Opinions that I would see as acceptable would be advice, recommendation or judgement based on experience. My impression is however that those differences are sometimes brushed away to quickly and I would like to know, whether others also see the need for a more fine-grained treatment of "opinion based" questions.