This concept gets across an imperial theme quite nicely, but it also simplifies things too much. Basically, the standard dozen or so civs typically tricked out with all sorts of varied units and specialties have been swapped out for what amounts to a measly three of them that play a lot like one another anyhow. West and East are structured similarly, with builders constructing traditional Western city centers and Eastern ministries, warehouses, barracks, stables, and so forth. Only the Middle East stands out somewhat, and this is mostly just for portable buildings that can be unpacked without the assistance or any sort of worker unit. You need to get into the future era to notice anything interesting with these sides, as that's when you start seeing ideas like the Middle East's cloaked factory and camouflaged revolutionary guard, and the East's bioengineered units like the supersoldier and hulking mutant. Despite these variances, the styles of play are nearly identical no matter what part of the globe your empire calls home. You need to make accommodations for the blatant specialties noted in the paragraph above (which basically means you need to build cavalry with the Middle Easterners, research a lot of tech with the Westerners, and crank out the infantry with the Easterners), but aside from that this is all about the same old base building, resource gathering, and army rushing.