The problem is it's difficult to figure out whether The Warrior was a separate but similar idea to Kung Fu, or that The Warrior actually turned into Kung Fu. John Little, for example, claims (In Letters of the Dragon) that The Warrior became Kung Fu. There are also letters written to Larry Hartsell and to Taky Kimura where Bruce says he has "created a new TV series based on martial arts". In The Man Only I Knew, Linda says that Bruce only contributed ideas to Kung Fu.
In any case, it's been well documented that Howard Friedlander and Ed Spielman had originally written the story (intended as a movie) back in the 1960s. They sold it to Warner Bros in 1970. This, plus the fact that Ed Spielman and Howard Friedlander were given credit for the Kung Fu TV series, makes me think The Warrior was a separate but similar idea, and that Fred Weintraub poached some of Bruce's ideas and gave them to Jerry Thorpe (producer of Kung Fu).
The only things we know for sure is that Warner Bros had a martial arts TV project they were developing in 1971. Bruce and Fred Weintraub were having on-going discussions about it. Bruce was hoping to star in it, and that Fred tried to help out. But it wasn't ultimately up to Fred, and the lead role went to David Carradine. The project was called Kung Fu, and the credit went to Ed Spielman, Howard Friedlander and Jerry Thorpe.