The successor to the Wii will probably come in 3 years. The Wii would be the strongest console if it would be released last gen. The Wii 2 would be the strongest console if it would be released this gen.
At this time the hardware costs for a console with double the PS3s power will be so low.
The Wii could have 2Gb DDR3Ram and a quadcore CPU Plus an Graphics card on the level of an Nvidia 220 GT in 3 years for 250 Dollar.
it will crush the PS3 and Xbox with ease in terms of power. The progress in Computer tehnology is quick. A Wii2 at Xbox360 Level in 3 years could be released for 100 Dollar At the time the 360 will be just 100 Dollar.