Let's go back to pinning accepted answers.
(Usual disclaimer that this is my personal opinion, mod hat off, and I do not represent the view of the whole mod team here.)
Anecdotally, in every case I've seen on this site over the last year where the accepted answer is not the highest-voted answer, it's been a bad thing to not have the accepted answer pinned to the top.
Let's get the elephant in the room out of the way: story-ID questions. We have a whole site policy on question closure in our biggest tag which is based on acceptance. That policy hasn't changed, but it gets a little more confusing to apply when the accepted answer isn't at the top. You click through to what you think is a dupe target, the top answer is one story, but no, wait, that wasn't correct and the accepted answer is a completely different story.
Another common occurrence on SFF is when new canon is released that makes a previously correct answer outdated. Example. If the poster of the old answer is no longer active, the only way to get a correct answer is for someone to post a new one. And right now, the only way to get that correct answer to the top is to wait however many years necessary for it to get enough upvotes to pass the old, perhaps 100+ scoring, top answer. Back when accepted answers were pinned, the new correct answer could reach the top much faster, if the question poster was still active. (That's not always the case, of course - askers can go inactive just like answerers can - but at least sometimes there's a quick fix from an OP, rather than waiting for dozens of votes to tip the balance.)
A single user choosing the answer they want is not a reliable metric for correctness, true. But neither is the lottery of HNQ upvotes. Either with or without pinning accepted answers, we'll sometimes have wrong answers at the top. That's unavoidable. It is an imperfect universe. But:
- If a bad/wrong answer is accepted, the active community will normally react to that mistake by downvoting it, which provides a visible indication, on the answer itself, that it's not a good answer. Even if it's pinned to the top, the negative score sends a useful message to readers. A misguided OP only has a single vote, which is easy to counteract by just a few other voters among the active community members.
- If accepted answers aren't pinned to the top, and a wrong answer gets a lot of upvotes (usually from HNQ drive-by upvoters), it's very hard to counteract that positive score with the relatively few votes of active curators. Without pinning accepted answers, we can have wrong answers at the top with no indication that they're wrong (except comments). The only indication would be when you scroll down and find another answer accepted.
We also need to accept (pun unintended) the limitations of the system here. As far as I know, SE has no plans in the foreseeable future to make accepted-answer-pinning adjustable per tag (e.g. pin them to the top for story-identification and not for anything else), nor to create a different kind of pinning to the top that doesn't depend on the OP alone. Nij mentions the possibility of some kind of pinning that's orthogonal to OP preference, which could be a great idea, but in practice, we have only two choices - rank answers by score, or pin the OP's choice to the top - and other may-never-be possibilities are a distraction.