I still don't buy the theory that MOST will EVER understand that a negative vote is anything other than a black mark
I've never expressed this theory, but in any case what I just described would likely have the effect of shifting the votes more toward the positive scale and would harness more positive votes.
A couple days ago Nick and I were meeting and the subject came up. I told him that we'd need to do some more tweaking for the psychology of the voting system and explained how some people are taking voting very negatively. His response sums up the psychology pretty simply: "then let's just start everything at 1000 and then it won't be as negative".
He was joking but that's essentially the point. The value of the ratings isn't in the positive or negative numbers, but in the comparison of them. Strangely enough, some people used to tell us we shouldn't use negative numbers because our users would not be able to comprehend them (not the why, but the concept of a negative number itself) but I've always been pretty clear about how well it would be understood and how sensitive it would be.
So the system could be much more valuable, if the system trended more toward positive than negative, and the two improvements I recommended would do a lot to address that. By separating the content more it would mean less friction between, say, trivia and word games users and the politics crowd. After all, the politics guys wouldn't need to see all the trivia threads and wouldn't need to vote on them individually. Then the ratings for those threads would be more of an indication of worth within the microcosm of the community that is actually interested in them. So they'd be rated on the basis of being a good word game or not, and not on the basis of just being a word game.
And the idea to make replies auto vote up (unless the user votes down, of course) is similar to how tagging auto votes up already. The assumption is that if you are tagging (bookmarking) the topic it is one you find more interesting than the average thread. A similar assumption can be made that if you are replying to a post you find it more worthy of a reply than a post that you did not reply to.
So with more separation of the community's microcosms and more positive voting it would be more useful. Then there are cosmetic changes that can make the negative less of a focus for some. For example, only positive votes could be displayed while the conflation of positive and negative votes used for collapsing and positioning.
There are a lot of tweaks for the psychology of the negative voting that can help. The current voting has an imbalance of incentive toward negative voting because negative voting provides an immediate reward to the user (the content collapses) while positive voting does not as often (it makes the post never collapse, but most posts wouldn't have anyway). That alone could trend it positive enough, but there are a lot of other tweaks that can be tried if that's not enough.