The official site just posted a statement announcing that J.J. Abrams and Lawrence Kasdan are taking over screen writing duties for Michael Arndt. This is a bit of a bombshell and the internet is abuzz with rumors including some that indicate that dissatisfaction with the scrip was the reason Abrams considered abandoning the project around the time of San Diego Comic Con. There are also rumors that the pair of Abrams and Kasdan are starting over form scratch including all new characters, thus leading to the delay in casting news.
One fact from the official statement is that filming is now delayed until Spring 2014.