Might be bad -- in principle, it would be nice if we could sift through many comments as a community, so as to increase the number of good ones that can float to the top. If everyone who reads a bad comment votes it down, not that many will be inconvenienced by additional mediocre comments, and allowing folks to attempt comments they think might be good (and might not be) would plausibly increase the absolute quantity of good comments. (This depends on our ability to sort good comments to the top and mediocre ones to not-much-read locations, though.)

A second reason it might be bad is that commenting, and engaging with LW content more generally, increases the chances that the commenter will learn from it and do something with it. But, again, the costs may be prohibitive if such comments stay mixed with the best of LW.