Like this the system is putting a lot of weight on the users with more Karma... and I am guessing there are "many" more users with less than 1000 compared to those with more? Some people may never have a chance to state their opinion like this.
Rather, the opposite approach might work? Users with more than X karma can completely remove some comments, and say if your comment has been removed, you are not allowed to comment again for a specific period of time. If you post x rejected comments in a row then potentially you get banned.
EDIT - maybe a little off topic: another "comment" about comments - I notice you can up vote and down vote comments. I see this functionality sometimes is used to indicate agreement (or lack of) towards a comment. This as far as I cant tell is not the intended functionality, I am unsure however how this can be fixed easily.
So I would expect there to be a ton of active HN users with more than 1000 points.
If you are in this >1000 karma club, please approve this comment. I have been a user for 1044 days.
Since commenting is such a huge aspect of these sites for me, I'll probably frequent HN much less often since I won't be able to participate in conversation. PARTICULARLY, I won't be able to get in the early comments that are necessary for making high-karma. You can't have your comment show up an hour or so later after "approval," you'll only net a handful of upvotes, because you'll be buried under the high-scoring top comments by senior HN users.
Perhaps make a mid tier, say 500 karma, where you can't endorse users, but don't need endorsement?
Then again, I only say something whenever I feel I have something to add, rather than just blasting comments and hoping to get upvotes (and now, endorsements)
I think the point I was trying to make was that by turning it around it would require "less" active participation from the users and by default everyone gets a chance, but the really bad comments would still get removed I think. Anyway we shall see how it works out!