What I see is that we need to let Bruce go and see how there are MANY who have gone beyond him. I mean as far as spirit is concerned, Bruce's Master was J.Krishnamurti, if you really want to better yourself in that area, study J.Krishnamurti, Buddha, Lao-Tzu, Osho. As far as combat is concerned, I mean Albert Einstein created the atom bomb! The "secrets" that Bruce knew were small potatoes. You can see it before your own eyes, many people have surpassed Bruce in kicking ability, flexibility, strength, etc. Bruce pretty much only had a trump in speed, which is hard to gauge and that's why I think he focused so much energy in it.
He wanted to own something that nobody else could compare to on a fixed scale. But what cannot really be beaten, was his creativity and authenticity, that cannot be competed with, that is just something special that does not come by often. Like a Jesus, a Buddha, a MLK, a Malcomm X, a 2pac. Physically speaking, his level of athleticism can be passed with not much difficulty. Scientifically, the art of unarmed combat, shoot even someone like Mayweather who can barely read has that perfected. Realize, not to get stuck at Bruce, go beyond Bruce Lee, realize the potential within yourself. We are all naturally born Buddha's, Bruce was a Buddha. We are all equal to Bruce, we just have to realize it