In light of the variable voting powers that the new karma system has, I keep finding myself wanting to be able to vote less than my "full power" on a comment.
But in particular, the thing I think I always want in practice is to be able to downvote less than that. Downvoting a comment by 4 feels like a huge slap in the face, especially if the comment already has 4 or fewer points. I think the default downvote weight should probably be 1, or n/2, or something less than the default upvote weight. Upvoting is a positive community interaction, and downvoting, while necessary, is sort of a necessary evil at best.
I'm not sure whether I'd argue in favor of going further to actually enable choosing the amount for up/down votes, or just down-weighting downvoting.