Super Mario Sunshine is less the 3D Mario black sheep than the odd duck, which is good news in a series where games have included flying through space and threw your hat onto enemies to eat their mortal flesh, as revealed in a couple of 2002 interviews just now translated by Shmuplations (an archive of old Japanese developer interviews).
With Nintendo's decision to give Mario a water nozzle, producers Shigeru Miyamoto and Takashi Tezuka discuss various issues. It's unclear whether or not Mario would wear different outfits in the future.
Miyamoto stated that he wanted the GameCube Mario game to be "something wild," but they were still concerned about the initial concepts for F.L.U.D., since they wanted a more childlike, free-playing experience.
F.L.U.D.D. originally had ten or so nozzle nodes, but they eventually reduced to four because collecting nozzles in that manner felt more "Zelda-like" than suitable for Mario. They actually go into great depth about what separates the two franchises on a design level.
The interviews themselves contain a lot more information and stories, so be sure to see them for yourself. You may play Super Mario Sunshine on Switch... if you purchased Super Mario 3D All-Stars a couple years ago. Too bad! Nintendo hates you.