devonian makes excellent points; like Les Miserables, this show has all the political sensibility of a somewhat backwards 4 year-old-child - that is to say, none.
To equate the worlds of Madama Butterfly and Miss Saigon is morally naive. Japan was never a European colony, tossed, as Vietnam was, from the French to the Americans and abused by both. The lack of this world view from the musical makes it, intellectually and morally, little more than just another fluffy operetta, a la The Desert Song.
And speaking of morals, I'm always surprised at the adoring audience reaction to the song "The American Dream," given that it's nothing more than a paean to greed, materialism, sexism, etc. The Engineer is a morally repulsive character, he physically abuses Kim, he uses her and a child out of no love for them, but only to get what he wants, and yet the audience seems to just adore him. Now it's far from strange for American audiences to love manically id-driven characters, but to turn a blind eye to The Engineer's status as something more of a villain than hero strikes me as ... odd.