Considering the lacklustre specs of the Revolution/Go, I think the controller will actually save the console. If it's to be released after the more powerful 360 and alongside the PS3 then it seems to be the only thing going for it.
People upgrade for one reason, a more powerful machine, more features, they want more available to them. If I wanted to play a worse (hardware-wise) console then i'd play my PS2 and not bother with another. The Revolution can't offer better hardware, but it offers more innovation than it's competitors, something sorely lacking in the 'stale' modern games market.
Wheres_ has a point though. I thought the EyeToy would revolutionise gaming, but it was brushed aside to the regular category of 'accesory', like the DDR mat or Steering Wheel. Can't it be said that the same will happen to the Revolution controller? Only time, and a willing fanbase with loose pursestrings, will tell. It's rare that you see a console with a controller more original than it's games catalogue.