The Reddit visualization I'd most like to see is one of votes/comments over time on highly partisan (not necessarily political) topics. When I was using Reddit I perceived distinct "tides" in those cases.

Comments would swing up and down by double and triple digits as early burying/back-patting is overcome by more moderate opinions as the post rises in exposure. Likewise, having a post linked on other large forums would result in new waves of like-minded moderation.