I've always been a Nintendo kid. My first console was the NES, well before Iwata became affiliated with Nintendo, but since he worked for HAL before then, he was a producer for one of my favorite childhood games, Kirby's Dream Course.
I kind of became disengaged with Nintendo (well, any consoles really) after the Wii, but he was certainly integral to keeping Nintendo alive during the time where raw processing/graphical power was what console games were looking for. 55 is too young to die. RIP.
EDIT: Iwata died on the 11th, not the 13th, as an update to your first post.