After watching the GDC press conference and seeing that what Sony have for the casual gamer is basically a Wii Sports Resort knockoff.. I fail to see how Sony expect this to make any dent in Nintendo's market leadership whatsoever..
Sony need NEW experiences if they want success, just look at Wii Sports -> Wii Fit, completely different experiences.. People won't spend the money on something they see as just a shinier version of what's already available. Especially at anywhere near $400.