See Adobe's information on this: http://www.adobe.com/products/creativesuite/upgradeinfo.html (Google's #1 hit on 'adobe upgrade'! Who would have thought that!?)
It's rare that Adobe divulges any new features up front of upcoming new versions; CS6 seems no exception. Those that know are told not to tell, those that don't know can only guess, and hope.
This forum discussion on InDesignSecrets.com reveals about as much as can be publicly deduced from what Adobe has published: