"What they're doing already exists in one form on the PC," he said. "Our focus [with Miis] is always to be different and do something that's different." Miyamoto furthers his opinion by expressing how the Mii system embraces but isn't focused on the internet, while noting that the character system took 20 years to "come to fruition." We assume much of that time was just Miyamoto circling the idea in his head, as his GDC keynote places the Mii conception alongside the Nintendo 64 era.
"We are trying to do something that is different and create something that hasn't been there before," he said.
A caricature creation system may not have been done explicitly on consoles before, but we still wouldn't call it an entirely new concept. Nor would we give the same honor to Home, but their integration is indeed a first for game consoles.
Miyamoto went on to address the idea the user-generated content, citing it as an inevitability. "It's not simply the question of whether there is a game editor," he said. "It is what form does that editor take." We have some idea.
Also of note, Miyamoto gave the obvious revelation that a Wii fitness game, tentatively titled health pack or Wii Fit, is underway to ride the wave of success of Wii minigame collections Wii Play and Wii Sports.
[Update 1: There was some confusion as to what Miyamoto said in the third line and what we added following the quote. The editorial has been given its own paragraph so as to alleviate some confusion.]