I anticipate that one effect of this will be that there will be more threads simply saying "I agree" or "Good comment" since this will no longer be so visibly reflected by the voting.
I think that those threads will be downvoted same as always, and when they grey out it'll give other users the impression that those comments are less interesting/worthwhile than other comments.
And, to rant a teeny bit, that's what downvoting is used for. You don't downvote people that disagree with you or that say something you don't like. Downvoting is for removing comments that aren't relevant to the discussion. That's why they go grey. When I saw your comment, you'd been downvoted and greyed out, and you made a comment with a relevant or interesting point. You should not have been downvoted.
