Yes, Atlanta needs a station hub in the downtown Gulch. The proposed future Amtrak trains from Nashville, CHA, Savannah, Macon, JAX, DFW, & Montgomery will all need tracks and platforms for terminations and connections. Possible commuter north service from Bremen, Cartersville, Canton, Gainesville, Cedartown, Rome, & Athens will all have to travel thru Howell CP. As of now there are 4 parallel main tracks of NS &CSX from Howell to the downtown gulch, At one-time there was a 5th SOU team track west of those 4 that may allow restoration to a main track. But the CP at Howell does need vertical separation of NS from CSX for all these future services.
Future commuter service from the East -- Stone Mountain & Covington. Commuter service from Macon, Griffin, Manchester, LaGrange, & Columbus also possible, 4 Main tracks are feasible from East Point to the gulch.
So, any station built in the gulch will need a final plan for future additional station tracks as all these services are implemented. Probably design for max of 10 - 14 or whatever real estate allows max tracks and just build 4 - 6 with a loop to / from Howell. For a start that will give a location to store spare Amtrak cars & any private cars including NS office cars.
The NS 2 main tracks from Duluth to Howell has already space for a 3rd or 4th main track. That will be possible once the present Amtrak station is abandoned with some bridges needing another track space. Ga DOT has for several past years already built bridges and underpasses with room for 1 or more additional tracks,