This can't work organically, generation of content has to be performed in the mode of presentation sufficiently compatible with the mode of consumption. Taking out a portion of comments from a discussion raptures it, making it too tarnished to hold together. It takes human intelligence to selectively abbreviate a narrative, an automatic system that just takes track of some kind of threshold is incapable of doing that gracefully. Removing offensive outliers works, but little else. See also this comment, made before it was made possible to easily see comments' context.