In the most recent installment of Square's seemingly serial news program dedicated to keeping Final Fantasy X-2 in the spotlight on what amounts to a weekly basis, the Result Plate Program was introduced as a means through which players could change jobs in mid-fight. A slightly clearer explanation of the system has been provided, and it seems that the Result Plate does not actually change characters' jobs, strictly speaking. Rather, the plate offers a variety of skills common to multiple classes, which players can place there after learning them. These skills are then available regardless of a character's class.
This mechanism creates an interesting wrinkle in the Job System, which has historically limited characters to class-specific abilities, save for one or two additional skills in some cases. That said, Square isn't totally overthrowing these conventions; some skills will remain strictly job-specific, and there is a limited amount of space on each character's Plate.
A few details on the new job classes of Dark Gunner and Samurai have also come to light; it appears Dark Gunners are just Blue Mages warmed over, as the primary skill learned by Dark Gunners allows them to use certain monster skills. Samurai, meanwhile, are a throwback to FFV's katana-wielding warriors, although they too have been given a shiny new skill to use, a light beam attack.
In all likelihood, information will continue to flow on FFX-2 as it nears its March 13 release date in Japan. A North American release should follow, although there has yet to be any confirmation of a localization.