Seems a little high. If I had to do a mid-level prediction, 200 mil would probably be my bet. Near 100% growth, while pretty cool, seems like too much to hope for.
Maybe, but... that number wasn't worst case... I am expecting a higer % of people with 2 or 3 consoles from this generation of current video game users. Also, expanded audiance range increasing average age of consumer, a much higher increase in sales to females, and more countries. A big boost from China by the end of the generation alone could really increase WW numbers.