As a moderator on a high-activity site I see the "too many answers" Community auto-flag fairly often. This flag (on a question) says:
More than 10 answers posted in the last 7 days
(There's also a 30-answer version. You can probably guess how I know that.)
On our site, it's pretty common for a new question that hits the Hot Network Questions list to get 10 answers in the first day. And that's not a bad thing (for us). When I get one of these flags I page through the answers looking for anything explosive, downvoted answers, deleted answers, and spam. If something stands out I handle it, but usually I end up just dismissing the flag.
What I don't do is try to determine if there are duplicates, or evaluate the quality of not-obviously-bad answers -- not my job. The community needs to take the lead there. And they won't know that there's answer-review work to be done unless they come across the question on their own or somebody brings it up, because they don't see the flag.
Could we do something better with this flag? I think any of the following would be better than what we have now:
Don't raise the flag on new questions. They're on the front page and, being new, are more likely to be read. Possible implementation: don't count answers posted within the first 24 hours after the question was asked.
Count only answers that are score 0 (-1?) or below.
Instead of raising a moderator flag, send these questions to a new review queue, perhaps "Oft-Answered Questions". Some design work is needed here because the question goes to the queue but actions need to be taken on answers.
How can we make this flag more helpful to active communities?