It's not a huge burden, but we're already seeing some negative effects worth discussing. For example I have now twice paid the 5 karma penalty replying to downvoted comments which were not trolling at all; they were downvoted because people disagreed with what they were proposing.
If we decide to wait two weeks, we need to decide on specific criteria that we will judge in two weeks' time to decide whether to modify or remove the new feature. If the new feature stays anyway because a few people decide unilaterally, then we might as well discuss it now.
The recent implementation of a -5 karma penalty for replying to comments that are at -3 or below has clearly met with some disagreement and controversy. See http://lesswrong.com/r/discussion/lw/eb9/meta_karma_for_last_30_days/7aon . However, at the same time, it seems that Eliezer's observation that trolling and related problems have over time gotten worse here may be correct. It may be that this an inevitable consequence of growth, but it may be that it can be handled or reduced with some solution or set of solutions. I'm starting this discussion thread for people to propose possible solutions. To minimize anchoring bias and related problems, I'm not going to include my ideas in this header but in a comment below. People should think about the problem before reading proposed solutions (again to minimize anchoring issues).