In my opinion all the pavilions are a sterile and an Americanized stereotypical look at the rest of the world. Not that that is really a bad thing, as I don't go to EPCOT expecting to have realistically experienced another culture.
Japan is my favorite architecturally, although the food was infused with too much fat; very different than my real Japanese experiences in Osaka, Kyoto, and Tokyo. And the artwork of Mexico I think is best representation of any culture, and Central America for that matter, although I would like to have seen some more "Day of the Dead" pieces.
It is a small world after all, especially in America.