Personally I still think we should change the reward scheme from linear to something that will give an effective cap (as in a reward cap that can be exceeded but doing so would require an amount of MVests that will never be in existence) like logarithmic or square root or something... But I also feel that if a post has been rewarded more that flags should count towards it more as in if a post is at $1 then a $0.20 flag should be worth around $0.20 but if the post is at $500 a $0.20 flag should be worth something like $0.50 or something (I am just pulling numbers out of my ass) the point is the as the value of a post approaches its limits, the value of flags will increase semi-proportionally (actually might be logarithmically to make sense) and the value of upvoted will decrease at a semi-proportional rate.
This may not stop people from getting absurdly high rewards but it will make it difficult and make stopping collusive voting and abusive behaviors a lot easier.