This is more or less me thinking out loud, but why allow upvoting for new users and not downvoting? Does it not make sense to have a barrier to entry for each? Maybe the ability to upvote only happens after you've been here for 3 months and downvoting after 6 months? (I personally like tying those abilities to seniority vs. points as I tend not to comment often, but can easily identify a snarky comment that adds no value -- with no ability to downvote it).