I think it is not just lack of dirt that gives that impression.
The shine on the plane is very even. In real life the paint varies in shininess slightly, and there are small irregularities in the smoothness of the wing metal. Not that there is anything wrong with shine, it is seen a lot on old photos from the period, but it doesn't usually look that even, and it wouldn't show on panel lines etc. that are indented.
We have yet to see a WiP aircraft with part-shiny skin where panel lines and hatch edges don't shine, or where these edges deflect the light in some way. It would be nice if this was possible..but not essential of course.
I am hoping that the shine will be either linked to a separate bump map, or that it can be varied in some way.
I think there will be an editable shine bump map layer for the skins (just guessing though), though it might be disabled in the initial release if they use too many resources.
Oleg? Please comment!
As long as the shine is kept to a minimum it will look good anyway, and especially so if the skins are 'dirty'.
And as far as skins go: I'm certain there will be many user made ones available within the first couple of months of release, and I'm also sure that people will do a nice job of making used and dirty looking skins
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