Since chatty comment threads already get directed to chat why bother keeping the "too chatty" comment flag?
I don't ever recall its use being beneficial. I also don't like the fact that you can't actually determine if a comment is too chatty without visiting the post in question. The flag queue doesn't hold enough context to be able to determine if it really reaches the level that it needs moderator attention.
Do we need to bug moderators because someone added a "Thanks! This worked for me!" comment to an answer? I'd hate to think we were expected to eradicate all encouragement or kind words from a post. Kinda not good for the community.
The "more than 20 comments" flag is more effective in indicating something actually needs to be peeped.
Why bother? Down with the "too chatty" flag!