DRG isn't useless as a job. It's just that there are so few of them that there is usually nobody present who needs the AF for DRG, BST, SAM, etc.
Honestly it would be nice if they just made a system where you collect Rare/Ex items from Dynamis, and then trade these GENERIC items to get the AF2 of your choice. However, chances are it's too late to implement this system without overhauling all of the existing Dynamis drops. Perhaps they will use this system for the upgrading of AF2 (i.e. get the "PLD Ex Item" inside of Dynamis-Y and trade it to a NPC along with any PLD AF2 piece to get the corresponding AF2+1)
So my best guess is that the 3 new areas drop the 3 city AF2.
In regards to timers, the way its worded on the website seems to indicate that the new areas will indeed be on a separate timer from current Dynamis.
XI Wiki

