In a recent interview with GI.biz, Nintendo VP of marketing, George Harrison, said that Sony and Microsoft have both attempted to woo the casual gamer but both failed due to a lack of understanding of the casual gamer. Specifically, Harrison mentioned the Sixaxis as Sony's failure:

"We can already see some of the things they've tried. For last year's E3, at the last minute, Sony rushed out their Sixaxis controller as an effort to respond to the Wii remote. We saw Microsoft roll out Viva Piñata as their killer app for the Pokemon set. And neither of those worked really well.

It's true that Nintendo knows how to dominate a certain kind of casual gamer market, but it seems a bit disingenuous to be writing off the Sixaxis as a failed attempt to capture Nintendo's market share. Sony has never particularly positioned that motion-sensitivity of the Sixaxis as a lure to the casual gamer. They've marketed it as a feature that adds to existing games and allows you to do things you've never done before (see LAIR and Warhawk). It's true that they have utilized the motion sensitivity aspect of the controller to create more easily accessible games like Blast Factor, flOw and Super Rub-a-Dub, but unlike Nintendo, thats that's clearly not their whole focus.