That’s an interesting suggestion. Though it would come with some challenges.
I looked at some stats for last month. My node stored on average 7.5TB and all audits added up to 6.9MB. So less than 1/1,000,000th of data is audited every month. If you would report all missing files as a failed audit, you’d probably instantly disqualify a node that would have easily survived just a few missing files.
So there’s have to be some system that weighs these self reported failures against normal audits.
Currently traffic is quite homogenic. With more mixed customer use in the future, this will change eventually though. You can’t build a system for now, it needs to work in all scenarios.