I'm on the fence about this project as a whole. I'd like to see HSR develop, and I think a 220mph Miami-Jacksonville-Atlanta-???-Chicago route would work, but I'm not sure about trying to run 220mph trains Atlanta to Savannah first, nor even running 220mph trains Atlanta to Savannah second. Macon to Savannah seems like it could be a Keystone-type operation branching off an Atlanta-Florida backbone with run-through traffic to Atlanta, rather than part of the backbone itself.
As to the station, the 17th Street Station idea seems to have fallen back again in favor of the downtown MMPT again. I personally favor a downtown station, though I'm concerned about the Crescent's operations unless the Beltline can be taken back for real railroad operations, or re-routed to go down by the Airport and through Montgomery and Mobile.
Expanded transit in and around Atlanta would be great, but the politico-socio climate doesn't currently support it. We might be able to get a rail line from Atlanta to Athens, but even local commuter rail just isn't really in the cards. Something that garners support from non metro-area politicians and citizens would be more likely to be funded, than an Atlanta-centric local system.
I agree that corridor service to Charlotte would be great, particularly once the SEHSR gets going north of Raleigh which might could allow for a day train Atlanta-New York or at least Washington. The Crescent currently does the 258 miles between Atlanta and Charlotte in five and a half hours. Or about 46 miles per hour. The Crescent 19 originating on December 2 was 25 minutes early into both stations. Not sure how early into Charlotte would affect run times between Charlotte and Atlanta, but pulling 30 minutes of padding off brings us down to 51mph average speed, pulling an hour off brings us down to 57mph.
Corridor service to Savannah with conventional equipment is a little tricker. There are two railroads from Macon to Savannah, the Georgia Central Railroad (Class III) and a Norfolk Southern route. Norfolk Southern is the obvious choice (ok, I'm guessing here) because of the potentially lesser upgrades probably needed. But in between Macon and Savannah, you have towns like Gordon, Tennile, and Millen with populations of 2k, 7k (including Sandersville), and 3.4k (12.4k total) respectively, though it does get you close to Savannah International Airport. The Georgia Central route goes through Dublin, and Vidalia with 16k and 10.4k (26.4k total) respectively. The GCR route already has double the population of the NS route. Both routes however meander a ways from the direct Macon-Savannah route, I-16.The interstate presents a third route. This gets you directly Dublin, Metter and not be unreasonable to drive to from Statesboro (Georgia Southern University). The populations are 16k, 3.8k, and 28.4k with a lot of seasonal traffic to and from Statesboro. By the time you build down I-16 however with all-new right of way, you might as well go the whole way with HSR as I can't imagine the RoW and track costs being so much more for 220mph than maybe 125mph (please correct me if I'm wrong about this). But even running 125, Macon and Savannah are 1:40ish apart, with Atlanta being another hour and a half at most from Macon (at conventional speeds). Running 220mph would put Macon and Savannah at just over an hour apart. However, running down I-16 wouldn't get you into downtown, and Statesboro would be a 15 minute drive from an I-16 station, though perhaps a new RoW could leave I-16 and have a station right at Georgia Southern before coming back toward Savannah. There would need to be a lot of eminent domain-ing of farmland, but I'm figuring this to be easier than in an urban/suburban setting.
Then there's also the issue of a Savannah station. Could the current one support corridor-level traffic? It's sure not very convenient to the city of Savannah. If I had my druthers, I'd put a large station right about where I-16 ends, over W. Gwinnett Street with some kind of connection to allow the Silvers access without a backing move. This location is about as close as you can get to Savannah without wrecking any neighborhoods.