One thing that will be incredibly useful is to limit comments from brand new accounts. A combination of vouching, limiting the posts velocity (5 daily limit), clear rules for new accounts, etc.

I understand we often see insightful comments from new accounts, but I always find it suspicious when non-throwaway accounts are created just in time only to make a quip.

This was discussed before. People will age accounts and buy/hack inactive ones. Meanwhile, often a link gets posted, the project owner (or someone affiliated) finds out, and they make a new account to comment; it would be a shame to lose these people.

I assumed that was how new people were encouraged to join in the first place!

https://xkcd.com/386/ "Duty Calls"