Based on the reviews I've seen of the Crystal Cove prototype, it looks like this new 1:1 head tracking, coupled with reduced motion blur, has eliminated a majority of the nausea from the experience (1).
So if Oculus holds up their end of the bargain, the next breakthrough is on the game developers. Who is going to create that 'killer app'? My bet is on Valve with something like Half Life 3 / LFD2 (2).
1 - http://arstechnica.com/gaming/2014/01/new-oculus-prototype-f... 2 - http://www.escapistmagazine.com/news/view/131719-Leaked-Sour...