I am no sure if the rewards has been changed as you mentioned in your post. .
I think that it is referred to the way the authors want to receive their payment. Only steem power; half steem power and half steem dollar; or simply decline payment. The option to decline payment is very useful in my opinion because help to avoid the hypocrisy in the situation, for example, where you are apologizing for plagiarism but the post is receiving a lot votes (money).
But, I am totally agree with your proposal of splitting at least 50% to curators.