Three problematic ideas seem to be common here:
- "Workplace expertise" is different than other expertise
- Question wording isn't important
- Answers should be moderated more harshly than questions
Having Workplace Expertise isn't really as unrealistic as some seem to think. When I ask a question about hiring process A which recruiters deal with day in day out, recruiters are my experts. They are people actively involved in the problem space of my question. Experts are people with experience in the specific problem domain.
Just because you didn't get a degree in firing employees doesn't mean that you, the HR person who's terminated 50 employees, do not have valuable expertise in that space.
Questions need to be focused to solicit expertise. This means they need to be focused around solving a problem and give some indication (implied or explicit) as to what sort of expertise is required. Generally it's someone who's solved this problem before (How do I bring up this issue to a coworker?) or someone at the "the other side of the table" (what do recruiters look for in an X?).
Opinions as in "What do you think" aren't answers. The problem with opinion isn't that it's subjective, it's that it doesn't solve a problem. If instead of saying "I think doing X would be a good move" you can say "Doing X has worked for me because..." or "I do X because in my experience..." you're moving into solving problems, not sharing opinions.
If the real problem in a question is only implicit, or some poor wording makes a question look bad but you think it really isn't, the question is worded poorly. If the question calls for opinion but you have a really great, constructive answer, the question is worded poorly.
Bad questions beget bad answers, and just because a question can get a good answer in it's current state doesn't mean it's good; a good question renders bad subjective answers as not answers to the actual question. If you see an asker is asking a great question but they've worded it in a non-constructive way, edit the question.
Bonus points; if your question's wording renders bad answers as non answers, they can appropriately be deleted by moderators (and users should flag such answers). But moderators aren't technically supposed to just delete bad, good faith answers to the question at hand.
Questions are people's first impression of the site, so it's very important that they be worded well. This is absolutely not a case where we can accept poor questions and focus on answers, especially given that the Stack Exchange system has great tools for moderation of questions but not answers. We can close, fix and reopen a question, but there's little the community can do about answers beyond editing, downvoting and commenting.
This isn't as easy as most people seem to think. Praying that people downvote isn't an effective solution; unless an answer is really terrible, people are reluctant to downvote due to our system. And I'm not very comfortable wholesale deleting good faith answers, even if they're not great or largely repeat other answers; unless there's a firm, community created policy on which answers we should delete, I'm extremely reluctant to delete other people's work. Closing a question is much less significant than shooting down answers.
If you have an idea for a stricter, community enforceable answer moderation policy, bring it up on this meta question.