His lack of development was to take your mind off the lack of character development and terrible writing of Sadie Adler who goes from farm hand, to a woman who suddenly gains 15-20 years of gunfighting experience by threatening the camp cook with a knife and an outfit change.
There is a mod that removes her completely from the game, it makes her invisible and deletes her voice lines, and it makes her missions sound like Arthur and John is talking to themselves. I forgot she was even a character until i replayed the game and forgot to install the mod again.