I missed some of the earlier threads and didn't want to reignite them. I feel more comfortable replying to PhilGoetz's comment since it's only from two days ago.

One problem that I didn't see anyone discuss is that this feature is likely to drive away new users. This policy discourages interaction with new users because unpopular comments overlap significantly with comments from new users. By discouraging commenters from responding to the low quality posts of new users, we disincentivize the picking of low hanging fruit, which is the opposite of what we should be doing. In addition, by doling out karma penalties at a set level rather than as a fraction of total accumulated karma, new users face much heavier fees than regular users, which will also result in increased insularity.