True but I think there's still an element of falsifiability to a teacher's evaluation of an essay that doesn't exist in an oral exam or interactive discussion. An essay is an artifact and if a teacher is giving student A worse grades than student B, a third party can look at that artifact to see whether it's remotely reasonable. A 1:1 discussion or an oral defense is much more subjective.
Not saying this is a fatal flaw, but there is a bit of a tradeoff there.
Not saying this is a fatal flaw, but there is a bit of a tradeoff there.