The release date switch is intriguing since we just reported last week that Fox is setting the Ridley Scott sci-fi project Prometheus with the same March 9, 2012 release date. The move also leaves a prime June 8, 2012 release date open. We'll have to see if another movie moves into that date.
It is also interesting that back in August, Disney set both Frankenweenie and John Carter of Mars release dates at the same time, a pattern they seem to be repeating with this move.
Frankenweenie was released October 5th, 2012 and stars Catherine O'Hara, Martin Short, Martin Landau, Winona Ryder, Charlie Tahan, Atticus Shaffer, Robert Capron, Christopher Lee. The film is directed by Tim Burton.
John Carter was released March 9th, 2012 and stars Taylor Kitsch, Lynn Collins, Samantha Morton, Willem Dafoe, Thomas Haden Church, Mark Strong, Ciarán Hinds, Dominic West. The film is directed by Andrew Stanton.