Sometimes I forget this is a house of formation and not a regular post-graduate academic institution. We often have oral exams. Many guys leap at that opportunity, but in many ways orals are more difficult than written exams. You don't have as much time to think since the professor is sitting across from you at his desk, waiting. You have to study harder in order to have the information readily available.
I just had my oral final exam in ethics. Fr. Andrews asked me to explain Kant's deontological theory of ethics and stopped me after two minutes or so. "Ok, you obviously know that. Tell me about natural law." Another two minutes, "Ok ok, you know that pretty well too. Anything else on any other topic we've studied in class?"
They do oral exams because in a real sense all of the seven years I'm here will be aimed toward making me a good preacher. Most of the people in the parish will only see you on Sunday morning. The sermon/homily is your one interaction with them all week so you have to have that gift of cramming as much information as possible into ten minutes or less. You have to hold their attention, communicate real content, and resist the temptation to easy one-shot gimmicks. And as many, many lay people have told me, not many priests have that talent. Fr. Stevens says you should always look at the readings for that Sunday and ask yourself, "What questions do these readings pose to us?" Do that, and the homily is already halfway finished.