I remember reading in, I believe, The Making of Star Trek, how Harlan Ellison was quite upset with Gene Roddenberry over the rewriting Roddenberry did on Ellison's script The City on the Edge of Forever. He was so upset that, while waiting in the outer office, he supposedly picked up some cord or twine that was nearby, fashioned a hangman's noose, threw it over a pipe running through the room just under the ceiling and, when Roddenberry walked out of his office, Ellison pointed at the noose and said, "Tell me it's not true someone re-wrote my words."
I remember reading comments by Roddenberry that included him saying, "He had Scotty selling drugs," and that the original script had Kirk and Spock arrive in the middle of worker riots and that many other parts made the script too expensive.
I also remember an interview (I think it was in the photo-novel) where Ellison made some comment like, "If they loved the version that aired, they would have been crazy over the original."
How did Ellison's original script differ from the final version that we saw on screen?