I think it's a good idea, as the quality of comments have been degrading.
Perhaps after a post has reached a certain age (few hours) comments would slowly open up to users with less and less karma. Just a thought, but I agree a "show pending" toggle would be nice too.
It is important that we encourage new users to comment on HN. The reality is that early posts from new users may not make the grade set by 1000+ Karma users. Let them be visible as otherwise you may discourage such new users from re engaging/commenting further.
Color coding comments to flag they as 'pending' is fine. But complete hiding them sounds too strong
Its great to have the conversation on how to improve HN comments
Perhaps after a post has reached a certain age (few hours) comments would slowly open up to users with less and less karma. Just a thought, but I agree a "show pending" toggle would be nice too.