I don't find "Jap" any more of a slur than "Yank", "Brit", "Nip", "Kraut", or "Jerry". In the context of WWII even "NAZI" isn't a slur, it is an accurate description of the opposition.
I am already annoyed by the fact that aircraft model kits (and flight sims) are leaving off the swastikas on German aircraft markings. People who had just been through WWII and suffered NAZI attrocities never complained about the markings of model kits, why are we so concerned now?
What is so "correct" about revisionist history where anything we find offensive gets edited out? If historical terms such as "Jap" and "NAZI" and aircraft historically marked with swastikas are so offensive, what are we doing playing a game based on killing?
The models hanging from my ceiling are marked as correctly as my skills permit. If you compare a photo of the plane in question to my model, they are nearly identical except for the fingerprints and brushmarks from a sloppy paint job and any errors caused by a faulty decal set. Of my 8 WWII Luftwaffe aircraft, 4 have swastikas. I did not omit them from the other aicraft, they simply were not present on those units.
How come there is no "politically correct" reaction to the red star of the Soviet Union? Stalin and friends tortured and killed as many people for no good reason. Yet I see no pleas to revise the markings of Soviet aircraft so they don't offend anyone who might have been persecuted by the Soviets.
To me, "political correctness" is merely the "politically correct" term for "good-hearted" censorship. Whether I like what someone else says or not, I don't believe in censorship in any way shape or form. I believe in using honest direct language as opposed to trying to come up with an alternative vocabulary that won't offend anyone. In the United States, the Constitution does not guarantee anyone's right to not be offended by what someone else says or does, but it sure as hell guarantees their freedom of speech. Too many people in the country seem to have forgotten that.
While I am ranting and raving on this subject, I would like to mention a story I heard on the news and my opinion about it. After September 11, a U.S. school prohibited displaying the American flag because some of the international students there might find our patriotism offensive.

Should we ban displays of flags or anything marked red, white, and blue on the 4th of July?
If you are not from this country and find our flag or its colors offensive, feel free to say so, feel free to buy one of your own and burn it for the news cameras, or better yet, feel free to leave. If you are from this country and you are worried that our flag might offend visitors, feel free to join those who are offended in any of the above activities, but don't you dare prohibit other Americans from showing pride in their country in public.