Patterns are unavoidable if someone is looking at them — I do hope that people actually read notes taken during exit interview.
My own underlying feeling is that if it’s gotten to an exit interview to air serious problems then the company (HR in particular) has utterly failed in its duty in looking after the safety and wellbeing of its employees. I personally wouldn’t trust such an organisation with detailed comments and criticism as I have no faith that it would either be used appropriately or remain confidential.
There’s just got to be a better way.