Bruce knew His ****.
That the top MA of his time thought he was very good, speaks volumes.
I don't think he was as revolutionary as many think he was, I think he was simply more open to common sense and what TRULY was the tradition of kung fu than many of his TCMA contemporaries.
I think that because he loved to read and study MA histories that he realized that the REAL tradition of MA is physical fitness AND fighting and if you don't do both you are NOT a MA.
He realized that the great MA of the past ALL cross trained and ALL cross tested their MA and developed their OWN systems of fighting.
He followed suit.
There is a lesson there.
Psalms 144:1
Praise be my Lord my Rock,
He trains my hands for war, my fingers for battle !