The problem I see is one more of content placement rather than zone size. How often do you go to such places as the Burning Wall in Eastern Thanalan, the Spriggan Dig in Central Shroud, or Monument Tower in Coerthus?

A few zones (South Shroud and Western La Noscea) may also have to many Aetherytes (Do we really need Camp Tranquil and Swiftperch?), but most zones are good with the one they have.