... then community with proof of brain will make their own decision whether to agree or disagree on the post reward based on that factor.

I think that should be the key anyway when it comes to evaluation and rewarding of posts ... I am not convinced that additional rules are necessary here, but I am also not completely against them ... lets wait and see what other community members think.

This is a great idea if the developer or anyone with technical skills can implement that,but need support by ...

True. I like to throw in ideas so that others may discuss them.

I think those big stakeholders have their own definitions for contents they see good for their own eyes/brain/emotional level satisfaction too.

Nevertheless, they should recognize (as I did), that actions which contribute to long term success of the blockchain (by attracting and retaining new users) are more beneficial in the long run than methods like circle-voting etc. which lead to a maximal short term profit.
Of course they can convey responsibility to curation services, but not everybody does that. I also only delegated a part of my STEEM power and prefer to vote myself with the bigger part of it.

For @haejin case, I think he is not that heavy abuser compares to some account that purely milking here ...

He is purely milking here with ten heavily rewarded copy and paste posts every single day!
What's the sense of being a social media platform if everybody rewards only himself? Imagine everybody started doing that? Should I do that, too? Fortunately, I just can't because it's against my principles.

In HIVE he stopped because other whales kept flagging him, which I really appreciate (oh yes, not everything is bad on HIVE but good here on STEEM - or reversed).
To stop people like @haejin there is one of the reasons why my curation rewards on HIVE are significantly higher than here on STEEM (because the remaining rewards pool for honest users is bigger).

Of course that doesn't mean I would defend HIVE witnesses or users who are also milking STEEM and cash out everything,