They were generally more inspection oriented and were light (somewhat) on documentation.
Frankly, nothing changed since 90's. They are still more concentrated on inspection and less on documentation.
Nevertheless I can't agree with you regarding GFSI benchmarked standards. We're certified via FSSC 22000 as well but in reality it's not so tough like AIB. Moreover I had experience some years ago with BRC but can't state that it has more benefits vs. AIB.
Maybe it depends on auditor... who knows.