misleading study advice, arbitrary exam marking and no legitimate review mechanisms.
I have been an ab initio instructor several times over my career, both in the classroom and simulator. What you allege cannot happen. The Academy is a Registered Training Organisation and subject to external oversight and audits. The exams and answers have to go through a separate vetting process prior to being used - beyond the instructor's control. If a trainee isn't happy with the marking, another instructor will also mark the paper. The answers have already been checked by the approval process.
As an RTO, students have both internal and external avenues of appeal and they use them. A corrupt instructor could not hide.
An ATC is required to have 100% knowledge. After an exam, the papers are handed back to the students and the instructor goes through the errors, explains the correct answers and the AIP/MATS references.
My experience is that too many students treat ATC learning as they treated school. They think that attendance will lead to success. They don't put in maximum effort to achieve the high standard required for field operations.