You wonder why oral exams are not more common?
There were 279 students enrolled in this class. Assuming a ten minute oral exam for each and two minutes to grade the answers it takes 55.8 hours to examine all the students. This oral exam would take at least two weeks in a 14 week semester, and ten minutes is really too little time to judge the work of an entire semester.
If anyone other than the professor grades the student, then they cry foul.
If the exams begin in the fifth week of the 14 week semester, the students examined last cry foul since they must study significantly more material.
There should be only twenty students in a class? Good luck with that. I suppose you could raise tuition and hire more professors or have the classes taught by lecturers.
Actually, in the USA most classes are taught by lecturers, and the classes are still huge.