with the Wii it all comes down to marketing, the game will Sell 3 million based off of name brand alone, if it is 9.5 quality or higher it will sell 5 million for sure... after that it will be up to whether or not Nintendo can brand it as an IT game. I think it is 9.5 quality and Nintendo is fairly succeful in introducing it to the new Wii audience.
It releases in mid october, and sell 4.5 to 5 million by Jan 1, 2012. It then will continue to sell well until the Wii gets replaced.... I think it become the best selling Zelda game ever at 8.7 million.
Zelda has never had a 90 million (by late 2011) to sell on TP was a launch title that kinda was lost in the shuffle in the initial WiiSports craze.
End of 2009 Predictions (Set, January 1st 2009)
Wii- 72 million 3rd Year Peak, better slate of releases
360- 37 million Should trend down slightly after 3rd year peak
PS3- 29 million Sales should pick up next year, 3rd year peak and price cut
