3) It'll be understandable
As gamers, we're used to controllers decked out with buttons, analog sticks and triggers. The average person is not. Sony helped bring video games to the mainstream, but it's not doing much to reach beyond tech-savvy non-gamers at this point. Instead, the PS3 may appeal more to high definition TV boffins and uber rich early adopters, leaving most of the world out in the standard definition cold.
Meanwhile anyone can glance at the Revolution's controller and get it. Why is the iPod so successful? Above all else it's extremely easy to use, and that's the Revolution controller through and through. No one's afraid to jump into a game of Ms. Pac-Man because there's nothing to "get." Nintendo's hoping to tap into that same feeling by appealing to everyone in the world with a pulse.
Above: Guitar Hero's controller. Simple to understand, and anyone can play.
If you've spent any time with Guitar Hero, you may have noticed just about anyone will give it shot. People are buying PS2s just to play it because it's obvious, comfortable, and fun. This audience of people, interested but not yet involved in gaming, will choose the next console king. A cheaper, friendlier system stands a better chance of winning that battle. The Revolution will be a great equalizer, appealing to people who haven't touched a controller since the NES. And guess what? The Revolution plays those games too.