What they should have done about Clayton Moore... (Spoilers)
When it comes to the battle over the rights to the Lone Ranger, it was always going to be seen as TV's hero versus the big bad money-hungry producer.
The Lone Ranger mythology includes an old man running the silver mine from which the Ranger gets his signature silver bullets; an ex-US Marshal who was a mentor to John Reid and his brother. They should have given Clayton Moore a cameo as that guy. He could have worn his fake beard and played the "old man" routine from whenever he would disguise himself as one in the series. They could have even thrown in a mythology gag where he tried on the Ranger's mask for himself.
Ideally, it would have brought a nostalgic smile or two to fans of the old show. At worst, the dated quality of the performance would have emphasized why it was time for a new Lone Ranger. Either way, it would have come across as a passing of the torch.
That's not to say that the rest of the film didn't have it's problems, but it wouldn't have been a flop due to their hounding of Clayton Moore over the mask.