because the downvote is critical to enabling people to accurately value content
Not that it matters, 'cause it's not going to change, but I don't actually believe that. Every other market in the world works without negative prices. I think an alternate solution might be possible with something like a 2nd price auction.
"...The theoretical nicety of second price auctions, first pointed out by William Vickrey, is that bidding one's true value is a dominant strategy...."
Between that and vote removal (un-vote), I think the system could address all of the problems that downvotes address, without the flag wars. Of course, I'm not going to do the hard work it would take to prove (or disprove) that, so it's only a guess. ; -)
Except for fighting abuse, how would you manage that without flagging?
For people who accidentally vote an abusive posts, you'd use vote removal. "Consumer Reports" style services (bots) could even be established to automatically remove upvotes on posts that are identified as abusive, so (eventually) it wouldn't even be a manual process.
For people who would intentionally vote on abusive posts, they'd need two votes to get a payout, so they'd be forced to split their voting power and payout would be valued from just under half of their voting power. Therefore, instead of wasting half their voting power, it should be more profitable to use their full voting strength to vote for non-abusive posts.
Yeah... not sure how much you have dealt with getting people to remove their votes but its not easy. There is no good way to contact people, some people log out for days/weeks at a time, some people just don't care at all.
Sometimes you don't discover a post is plagiarized until the last minute, say 2 hours until payout, and there is no way to get 10 different people to remove votes in that time.
There is no practical way to do it without flagging.
Maybe, but it's still an open question as to whether the harm of flag wars outweighs the harm of some percentage of low quality posts earning unjustified rewards.
I'd be ok with getting rid of flagging if there were some other mechanism to deal with plagiarism/abuse, but there isn't an alternative.
I think that being able to remove the financial incentive for plagiarism helps to somewhat keep it down. If you make it so that there is no punishment whatsoever I think people would be encouraged to do it even more than they do now.