Let's take a look at the two Com/Sci civs:
Greeks: Start close to Romans, Egyptians, Persians, and northern Europe civs. Their special unit, hoplite, is purely a defence unit, having no equal until the Middle Ages. This civ will probably only be able to expand if they can get a hoplite in a new city quickly so the Roman and Persian UUs don't topple their empire. Otherwise they are effectively a titanium wall from maybe Anatolia to the Balkans for probably over 150 game turns.
Persians: Start close to Greeks, Egyptians, Bablyonians, and Indians. Strong infantry UU, maybe finding an equal in the Roman Legion. They will probably be able to strike out against the Egyptians and Babylonians (early UU) and the Indians (mid-late ancient UU) but be rebutted by the Greeks, forcing them to expand east instead of west. If Persians withstand withering extremely early Babylonian/Egyptian attacks they will probably be
the force in the Middle East for centuries. Their territory will probably include the Fertile Crecent, Egypt, and northern India, bordering China quite farther than they actually did in real life. If the Greeks don't beat them to it they they might sneak up into Russia, creating a huge frontier that only the northern Europeans could attack.
This is all assuming that we are playing on Earth, which I always do.