Please Rich (for the love of God), please do not interpret this as an attack because I mean this in the most pragmatic of tones: I think you're missing the point. The monument is not intended to single out Iwo Jima as the only significant battle, the monument uses an image which represents the struggle, sacrifice, and ultimate victory of United States soldiers in WWII. The fact that it happened to be a real image from a particular battle is incidental; it doesn't mean the other battles are insignificant.
I would also point out that there is, in fact, a memorial the encompasses a much greater breadth of WWII.
http://www.wwiimemorial.com/ One could argue, though, that this memorial is beautiful but lacks the human element so powerfully conveyed by the Iwo Jima statue. One doesn't have more value than the other, they're just different.