Sharkman,
Here is the way I look at the weathering. Have you ever been to a car show? All those beautiful cars from the 40s and 50s. They are spotless, they clean them with toothbrushes for pete's sake! I was around in the 40s and 50s and I can tell you those same cars being used on the street didn't look like that at all!
Restoring aircraft is a lot more expensive than restoring cars. I would be willing to bet that no aircraft in WW II looked anything like those spitfires. In my many years, I have looked at what must be tens or hundreds of thousands of WW II aircraft, taken during the war, and I have sometimes wondered if we were weathering them enough! Most were filthy. I think their primary concern was their airworthiness. The all important consideration was whether or not the planes could get you there and back. Being show clean was most likely waaaaay down on the list of priorities.
Something I might add, when I do occasionally see models that are over weathered, it is usually that they are over weathered in scale. I have always looked at unweathered planes and armor, ships, etc., and thought they had a toy-like appearance.
Just my opinion!
Bob