I think CenturionStrategy is right about Carth --- they blow on the Zone. I hate being them, Greek, and Choson. Babs aren't that bad. Palmy isn't on the bottom. I win with Palmy a lot on Conti maps in random civs.
I would say:
Top Races in RM:
Shang, Hittite, Minoan (On water maps)
Good Races in RM:
Yams, Assy, Mace, Roman, Egypt, Babs, Sumer, Phoen, and Palmy.
Poor Races in RM:
Carth, Greek, Choson, and Persia.
The poor races all have something in common.... they are gold civs with bonuses that can't be utilized because they are long dead before their strengths can be used.
If I had to pick one civ to be all the time I would probably pick Shang. I could compete on any map, with any amount of players, and it would be versatile enough to keep game exciting. I could boom bigger or rush better than any other civ with all military options open in Tool and Bronze.