How many of you have actually clicked the link and seen the actual proposals?
Animated demonstration at USAToday.com
Its not so much about having a runway on an gradient, its more about always having the terminal right at the end of the runway for arrivals, and right at the beginning for departures. This virtually eliminates taxiing, thereby saving fuel. No hump in the middle of the runway. No idling on the ground.
Personally I think its pretty ingenious. Not saying it will work, but the discussion would be more informed if people were aware of what they were debating rather than throwing negative comments around willy nilly...