Is there actually any value in defining deterrent buffet formally and generically?
Surely this is an area where TP opinion should be paramount - defining and deciding what is adequately deterrent. That should surely include aspects of the aircraft role and ergonomics, plus task assessment as some tasks will take up greater aircrew attention than others, and hence need a much more obvious and obtrusive form of warning symptoms, such as pre-stall buffet.
But surely in all cases, deterrent buffet is about deterring a pilot from taking the aircraft further into an unsafe region. To use your extreme example of an aircraft being physically damaged, well I'd argue that if that was reached, then whatever deterrent effect was there, it wasn't deterring enough!
G