Iwata also said that he thinks it is unlikely WSR will lift up Wii sales "2 to 3 times," which is what it will need to return to last year's levels and put Nintendo on pace for their sales target. This came in the exact same responce that the 6-8 weeks quote came from.
So in the best case scenario, it will take a combination of WSR, Wii Fit Plus, NSMBW and other games to get Wii sales all the way back up. NSMBW is the only one that might drive tons and tons of hardware all by itself, since the others are sequels to Wii games.
I'd look for a black Wii, and NSMBW as an alternate pack-in game before a price cut though. They can still make a price cut or introduce new SKUs basically all the way up to the week of black friday.
"[Our former customers] are unable to find software which they WANT to play."
"The way to solve this problem lies in how to communicate what kind of games [they CAN play]."
Satoru Iwata, Nintendo President. Only slightly paraphrased.
