Atlanta has only had one race since 2011.
Any track not owned by ISC or SMI has an insanely hard time getting a Cup date (hopefully this will be changing). Aside from that I know the track has some issues with how NASCAR operates (mainly the closed pits, full-course cautions and wet weather racing), although I'm not sure if that would prevent them from pursuing a Cup date.
I'd imagine Mid-Ohio and MoSport are pretty high up the list, I could also see them trying something out of left field and trying to imitate IndyCar's success at Portland.
Aside from road courses, I would love to see them give Iowa a try, even though the attendance at every other race gives them no reason to. A trip to Gateway would also be interesting.