I think this goes against the ideas the curators of HN have for HN. For the simple goal of furthering (meaningful) conversation, I think dropping comments would be better.
On the other hand, I think it'll drop the number of really good comments -- those where commenters go out and lookup a few (possibly obscure, but very interesting) references. Doing that kind of work, just to have the text be deleted with hardly anyone seeing it doesn't seem worth it.
Which brings us back to the question of "What should HN be, for whom -- and how do we achieve that?".
On the other hand, I think it'll drop the number of really good comments -- those where commenters go out and lookup a few (possibly obscure, but very interesting) references. Doing that kind of work, just to have the text be deleted with hardly anyone seeing it doesn't seem worth it.
Which brings us back to the question of "What should HN be, for whom -- and how do we achieve that?".