There are so many things wrong with this movie that it is hard to pick just a few. Let's start with the silly and annoying songs. Like "Ride Little Cowboy" which just tended to accentuate the city-slickers look of Klinton Spilsbury. The silly kiddie cowboy songs going on in the background during the movie hurt any credibility or momentum that the story had going for it.
I had seen the media hype before this movie was released, and I saw Klinton Spilsbury interviewed on various TV shows, and he had a very soft, sweet, lilting voice. His body language was not exactly what people remembered who were fans of Clayton Moore and the Lone Ranger TV series. Spilsbury did not help things by acting like a diva and talking trash about Clayton Moore after the Producers got an injunction prohibiting Moore from appearing at Conventions and other events as the original Lone Ranger. Clayton Moore was not even allowed to sign as "Clayton Moore, The Lone Ranger." He could only sign as "The Masked Man." The incredible amount of negative publicity that this move gave the film was only added to by the petulant attitude of Spilsbury who was very quick to tell reporters that Clayton Moore would be quickly forgotten once the movie came out!
Sadly, even after the movie was a total flop, the company that owned The Lone Ranger refused to lift their Injunction against Clayton Moore, and he was never again permitted to sign anything except as "The Masked Man" and he could not don his black mask at any public appearances. Between Spilsbury's diva personality and the negative publicity the movie got, it certainly did not help to make a good impression on the public. Worse yet, a few weeks before the movie was finally released, the news was leaked that Spilsbury's voice in the movie had been over-dubbed by James Keech because the Producers thought that Spilsbury did not sound very convincing as a cowboy. The ridicule and derision that this news brought on the talk shows and comedy shows of that era put the last nail into the coffin.
But then there was Merle Haggard narrating his way through the movie. Apparently, the Producers were hoping that the macho image of Haggard (one of the Outlaws of Country Music) would add credibility to Spilsbury as The Lone Ranger. The narration by Merle Haggard was just another annoyance that audiences had to deal with. At times Haggard rhymes his narration, and it sounds like some weird kiddie movie. Combine the rhyming narration with the "Ride Little Cowboy" songs and any credibility that Spilsbury could have mustered was destroyed by Haggard and the soundtrack.
Tonto was played by Michael Horse, and as others have pointed out, Horse had a lot more personality than Spilsbury. In fact, perhaps because of Spilsbury's allegedly combative attitude during filming, it seems like Horse was given a lot more dialogue and screen time than anyone would have expected of Tonto. Tonto takes charge and often is the leader instead of the Lone Ranger. I was expecting (or hoping) that Billy Jack would make a cameo as Tonto's brother (it would have made the movie a lot better). Horse is not only more interesting than Spilsbury, but he says more and has better scenes. Perhaps it was a case of Horse stealing the show from Spilsbury. However, since the movie was so wretched, Horse did not get much recognition. Unlike Spilsbury, Horse has had a very productive career in the film industry.
Perhaps the last negative about this movie is the Powder Blue outfit of The Lone Ranger. The material that was chosen for Spilsbury was more powdery blue than what Clayton Moore normally wore at appearances. That choice of color for the outfit just made Spilsbury look more effeminate in his role. The comic book version had shown The Lone Ranger also wearing a red shirt and black pants, and that alternative outfit would have helped Spilsbury look more convincing as The Lone Ranger.
The supporting cast mostly mailed in their performances. They all look as if they were working on a TV episode and nobody seemed very convincing. Even the villain, Cavendish lost his edge due to the people around him. Overall, I feel sorry for Spilsbury. Not only did he do a terrible acting job, but it is obvious that the production and publicity were horrible and effectively sabotaged any chance the poor guy had. Even if he had been an excellent replacement for Clayton Moore, I doubt that the movie would have done well as a result of the other factors. As it stands, this film is funny in a sad way.