The character of Matt Decker was devised by writer Norman Spinrad. The producers of Star Trek: The Original Series initially asked him to write a part for Robert Ryan. Intending to take inspiration for the plot of "The Doomsday Machine" from the story of Moby Dick, Spinrad developed the role as being similar to Captain Ahab. The character was intentionally made less intense after William Windom was instead cast as Matt Decker. Stated Spinrad, "Things had to be adjusted. I had to make him a little softer, and I think it might have taken some of the edge off of the story. In the original version, Commodore Decker was much stronger. They don't find him slumped over in the ruined ship. Instead, they find him staring out the viewscreen and in a very bad mood. There was also the feeling that a guest star with that kind of presence would overshadow Captain Kirk, and therefore his character had to be toned down and his lines reduced
I recall at the point Spock relieved Decker from Command was Intense !
.
One Knew Decker wouldn’t go Quietly
But hijacking the shuttle craft was an
Unexpected twist!
Spinrad is a great writer, it would have been great to see his original version.