Words per post have nothing to do with quality.
You don't seem to understand that the whole reason for curating and rewarding people is to filter posts for quality.
Your solution just pays people for posting - so you put some rules about minimum words - that means nothing. Somebody could use a bot to churn out posts that meet the criteria and get the payout.
If the system is able to pay out automatically then it is possible for a bot to be designed which can make posts that meet that criteria. @dahaz159 has pointed out why your system could never work.
Dan and Ned are not stupid they have thought long and hard about the current system.
The geniuses of the community have come up with the current system.
It is not perfect but nothing is.
The number of words was just to answer your comment about an author who automatically gain rewards even posting 1 sentence.
With regards to the quality of the content, that's another story. Rules must design properly to avoid abuse and the with the existing smart people in the community, I believe designing and implementing the rules is not a problem.
That's not really an answer. You are suggesting a change which ruins the way the old system works but your solution to the problems is "someone else will think of it". Maybe the others will think of a solution or maybe not.