Is it really a good idea for upvotes to give +10 points and downvotes only -2? I've noticed that downvoting posts often produces "sympathy" upvotes by other users seeking to maintain the vote total at a certain level. I have no problem with this "strategic" (vs. "sincere") voting, which seems inevitable to me given human voting behavior in other contexts. However, the combination of asymmetry with the tendency toward strategic voting produces two undesirable side effects:
(1) I often suspect that if I downvote something, there is a large enough chance that someone else will upvote it that the expected net point gain will be positive, so I won't downvote and therefore my information about the quality of the post is never taken into account.
(2) Controversial posts get a large net point gain, which is bad enough by itself, and may even create an incentive to stir up controversy.
I understand the bias toward positivity (I'm not arguing that the reputation of the average user should be zero) but it seems like enough of a positive bias is already present in people's voting behavior that the +10/-2 asymmetry is redundant at best, even ignoring the side effects mentioned above.
What do other people think about this asymmetry, and is there anything we can do to change it?