I saw "Letters..." I thought it was a very good movie. I didn't think that it sanitized the Japanese. It showed a couple of Japanese who were scared young men filled with doubt, and most of the Japanese were simply doing whatever they could to fight and die "honorably". But it did not draw any equivalence between American and Japanese societies of the time, or between the overall conduct of our respective militaries. It just showed the experiences of a handful of soldiers in one particular (losing) battle.
That's what I saw, too. Maybe there should have been less of a focus on the younger, nicer guys -- if it's true, as one poster says, that the Iwo troops were really hard-asses. But in any case, a good movie. Strict historical accuracy, although both desirable and achievable, is very rare in movies. However, there are worse things than inaccuracy. I believe Eastwood made not only a riveting film, but a basically honest one.