The rewards for curation have actually been re-configured to favor small holders and to prevent bot abuse.
However, some investors have bought a lot of steem or invested in mining hardware and they want to see their investment being returned somehow, that return on invest comes on the form of curation and I think is fair to retribute them.
I do believe who have invested should profit but their influence should be (almost) at par when curating. I have no clue how this can be implemented but it was just a thought. Which ever way I just want fairness and in no way am implying it is not at the moment.