I agree with potential bot-fraud becoming a serious and large issue. However, I am unsure that incentive curves can fully stop it. Right now I'd guess the Flagging system + the heavily weighted incentive curve doesn't make it worthwhile?

IMO a better solution would be to try to find a way to link voting to actual attention and enjoyment as opposed to just a "click-to-vote." What Brave is doing with their BAT is interesting in that realm: https://steemit.com/blockchain/@hellhen/a-blockchain-based-online-advertising-system. Could also address issues with autovoting, voting blocs, etc.