If you are asking in /r/AskHistorians it means you don't know about that topic and need someone who does know what they're talking about to come and give insight. The person who likely doesn't know anything about the topic at hand (who asked the question) should not be the one determining whether or not a question has been answered to its fullest or most correct extent. To ask the mods to comb through every thread constantly to determine whether a question has been 'answered' is an even sillier proposition in my opinion. The best solution is to delete unsourced conjecture and general shitty comments and just let people post and let the good answers remain through a system of strict guidelines.

Further, by labeling a question as "answered" you basically tell everyone else who could provide another level of insight to that question to sod off. The questioner is already satisfied so you don't matter and go move onto another question. Labeling questions as answered, for this reason alone, is fundamentally harmful toward the experience that is attempted to be achieved here.

That just sounds like something that would shut down potentially fruitful and useful discussion

One thing that I like about this subreddit is that there tends to be input from multiple knowledgeable people on a question. Someone will answer, and then other people will come and add more to the explanation or dispute aspects of the answer. I would worry that an "answered" button would come off as "someone gave an answer, thread finished" and discourage more input.

But this assumes some sort of ultimate truth exists or can be found.

I would suggest not. I am in no way qualified to know if a question I might ask was truly answered or if the answer that seems convincing to me is correct. The back and forth discussions are at least as illuminating as the first plausible (to me) answer.

Maybe the suggestion as proposed wouldn't work well, but I have the same frustration as the original poster when I see an interesting question only to find there's nothing there at all when I open up the thread.

I wonder whether we could change the comment counts on the front page so that it only counts extant comments (not deleted ones). This would resolve the issue, and give an indication of how much content there is to read.