I think national wonders serve a useful gameplay purpose for city specialization, but they need to be reconcepted. They shouldn't be "wonders" with names that imply a uniqueness and "wow factor" they do not have - Wall Street, Oxford University, the Globe, these are names for real wonders. Rather, they should just be "national buildings" or something. GalCiv2 called their equivalent buildings "capitals", so you built a Financial Capital, a Scientific Capital, a Cultural Capital, and so on. I think Civ could be a little more creative in naming, perhaps using Financial District, Research University, Museum of Art, and so on. The National Park and Iron Works were fine, generic buildings; the Epics would have been fine except for the oddity of treating a literary achievement like a building.
And the Moai Statues just made no sense on any level.