It's only around 10 years since instructing was done by PPL FIs, less for helicopters. Nothing remotely revolutionary or earth-shattering is being proposed, merely a return to how things were for years and years and years. And as bose-x said, standards were no different.
I'm an FI(H) who does happen to hold a CPL...because I had to. About 90% of the CPL theory was a complete and utter waste of time for a future instructor, and even if it wasn't, I've forgotten it anyway...use it or lose it. I'd have been far better off learning a bit more about how to teach, and learning theory covered about 1-2 lessons in the FI course.