According to Square Enix, Tidus was originally going to be a plumber in Final Fantasy X. This comes courtesy of a Famitsu interview with writer Kazushige Nojima, character designer Tetsuya Nomura, and producer Yoshinori Kitase. Here is a quote straight from Nojima.
“To get the character in the water, for the initial plan, there was a time in which Tidus was to be an underwater plumber.”
Tidus’ overalls were one thing that crossed over from his previous origins as a plumber, though they became a bit more “sporty” when it was decided he was an athlete. They were meant to be blue-collar work clothes and the traces of that can still be seen. It was Kitase who was responsible for Tidus becoming an athlete. There had never been aspects of sports in a Final Fantasy game before, and Kitase felt it would be a new challenge for the Final Fantasy team. He was also enamored by sports in science fiction titles. This gave Tidus a uniqueness among other Final Fantasy protagonists, which the developers were keen on. Kitase spoke to Nojima, and that’s all she wrote!
How different of a game do you think Final Fantasy X would be if Tidus were a plumber?