Depends on what control scheme they went with, the price they relased at and the software they went with.
If they stick to the same pattern of just more powerful traditional systems then no, Nitnendo would be fine with keeping the Wii on the market for a few more years, if on the other hand they relase systems that truly compete with Wii in terms of control and software and price, then Nintendo may have to release a new system within a year or two, but it wouldn't just be a Wii 2, it would be something that would innovate beyond what the Wii does.
Predictions:Sales of Wii Fit will surpass the combined sales of the Grand Theft Auto franchiseLifetime sales of Wii will surpass the combined sales of the entire Playstation family of consoles by 12/31/2015 Wii hardware sales will surpass the total hardware sales of the PS2 by 12/31/2010 Wii will have 50% marketshare or more by the end of 2008 (I was wrong!! It was a little over 48% only)Wii will surpass 45 Million in lifetime sales by the end of 2008 (I was wrong!! Nintendo Financials showed it fell slightly short of 45 million shipped by end of 2008)Wii will surpass 80 Million in lifetime sales by the end of 2009 (I was wrong!! Wii didn't even get to 70 Million)
