I wonder if there is an article or book out there that lists which ideas for the Big Boss plotline belonged to Bruce Lee, Lo Wei, or both.
Lo Wei's career after Bruce Lee was pretty much a dud, yes, but for what it's worth, Wei was the one who discovered the cinematographic potential of Jackie Chan and had him star in a few movies. 1976's Shaolin Wooden Man is actually a good movie in my opinion, but one could tell that Lo Wei was out of creative juice by that time; not that he had much of it to begin with.
Also worth of note is that another Lo Wei flick, A Man Called Tiger (1973) was meant to be Lee/Wei's third collaboration together. Needless to say, Bruce was already darn sick of him so it was not meant to be. The movie does have Jimmy Wang Yu and Maria Yi in starring roles.