Also I think the delay caused by waiting for endorsements on comments will really kill a lot of fast-moving comment threads. it will make it harder for people to have a discussion until the 1000+ karma gods take notice of the thread and throw enough endorsements around to make the comments visible.
So now every comment will look positive and be re-affirming instead of challenging someone to think, "Hey, I agree with that comment, but hundreds of others have disagreed, maybe I should read the thread to see why people disagree, maybe there is something I should learn about."
There is too much gaming of comments. Let people speak freely, moderate for illegal stuff, and be done with it.
I would suggest that the proposed damping system if introduced should be reviewed after a few months. I suspect however that the main effects will be qualitative and so hard to analyse. I have gained a lot from deeply forked comments where one person provides me with a fact or Web site.