That would definately help the situation in Japan.. However if anything I'd see this happening in 2010.. Well at least more likely..
Why? Well Nintendo will most likely want to drop the price of Wii in 2010 and this will allow them to give consumers that option but also to continue selling at $250 with an upgraded console with more value which is what Nintendo would prefer.
Another reason is that Nintendo will want consistant growth and if they release Wii Motion Plus and Wii Sports Resort Q2/Q3 2009, Wii Fit Plus Q4 2009 and then Wii Plus Q2/Q3 2010 along side smaller games, maybe Starfox or Paper Mario with The Legend of Zelda Wii coming in Q4, it makes a lot more sense that way (not saying that's what'll happen but it's the way Nintendo will be thinking)
I like what you said for upgrades except for the wireless sensor bar - no point.. and the wireless nunchuk.. more batteries, and a strap would be needed for that too..
How about a Wii Remote Plus with a built in battery? That'd be more useful
