@BnM You make some good points that are definitely feasible, and I think a March 2012 launch is possible but at E3 2011 the 3DS will have been out for 4 months already meaning their whole conference will be about software, and maybe 3DS/Wii integration (3DS as a controller anyone?). My point being, then and only then will we really get a clear view of whether Nintendo's plans for the Wii(2) are what Iwata and Reggie have been telling us or if it's a smoke screen. For now I'm taking them at their word because financially it makes sense as the Wii is still selling strong. If this holiday's sales are weak, and the weekly incentives don't pan out, I think a FY2011 will be necessary, but if those ideas work and 3DS compatibility boosts console sales significantly, Nintendo might even be able to wait for March 2013, since as you say MS and Sony are likely going to launch their next consoles in 2014-2015.
The lack of 1st party titles could be Nintendo's gift to 3rd parties who are weary of seeing their titles take a back seat on the Wii, and want their titles in the forefront of consumers minds which leads into my next point brought up by ThomasO:
With EA pushing their own vitality sensor peripheral (that NFL game actually looks cool especially with online leader boards) I wonder if Nintendo is rethinking or retooling that one. I don't know how EA managed to beat them to the punch, but they have been beaten, and it might be better for them to support EA's peripheral with software rather than trying to follow them, something Nintendo is not fond of doing. And it would also give 3rd parties a vote of confidence that Nintendo will be faithful in their support and plans to become more 3rd party friendly as evidenced by the 3DS.