Who else remembers using the Flesch-Kincaid Grade Level metric in Word to evaluate school essays? https://en.wikipedia.org/wiki/Flesch%E2%80%93Kincaid_readabi...

Imagine my surprise when I learned that this metric is not one that was created for authors to maximize: reading ease for the widest audience is not an objective in some deparments, but a requirement.

What metrics do and should online essay grading systems present? As continuous feedback to authors, or as final judgement?