I don't believe Georgia will ever do anything. I remember a demonstration train Atlanta-Macon-Savannah run with Amtrak equipment (Amfleet and an F40) in 1980. I was there at its departure from the former Terminal Station site, and the clipping from the Atlanta Constitution might still be in my files.
There are two directionality problems in Macon. The bridge used by CofG trains to enter the Macon station from the north has been removed. If a train runs south on the ex-Southern from Atlanta, it's pointed in the wrong direction to continue to Macon. These problems can be mitigated with a lengthy detour through the Brosnan Yard leads, but the better answer is reinstalling the bridge. Of course, to do that and to bring the ex-CofG up to 79 mph would cost $200+ million.
Yes, running a train Atlanta-Augusta-Millen-Savannah is theoretically possible, but then politics comes into play.
Note that almost all of the ex-CofG between Macon and Savannah is dark territory at 49 mph. Bringing it up to 79 mph would cost another nine figures. Also, although the ex-CofG station in Savannah is still standing, over half a mile of track has been removed to access it. And surely Amtrak would use the current station in Savannah, which is reachable from the ex-CofG.
There is also a question of the Atlanta station. I am 99.99% sure that NS would not allow an additional passenger train to use Peachtree a/k/a Brookwood Station and tie up its mainline more than Amtrak already does. This would force the issue of a new station for Atlanta... which has also been a topic of endless discussion without action.