Activision's doing it differently this time. For one thing, right there in the press release, it notes that "Ownership of submission remains with the creator." Last time, the competition had a caveat that if Activision decided to publish the winning entry, it would own the IP. The announcement of this contest mentions nothing about an Activision publishing deal being on the table.
Additionally, Activision is working with Indiecade to run this contest. Submissions are open now through December 31. Winners will be announced sometime in the next couple of years or whatever.