Body contours

Like he said, a lot of work to make it look right. 

I have seen a model which was worked over with an air eraser. That is an airbrush-sized sand blaster.  And like an airbrush it takes time and practice to pull off subtle effects.  First all of the underlying rib structure was protected with strips of masking tape. Then the oil-canning effect was blasted in. It takes time. More can always be removed. It is harder to add it back in. 

Natural metal is even more of a bear, getting the surface to be smooth, not grainy.   A by-product of the shot grit size.  

That being said, the relatively new AFV Club LST in 1:350 features some subtle oil-canning on thehull. 

I've seen some techniques to make the panels warped and misshapen, but it is a huge amount of work. I think it looks very convincing but I am not going to invest that amount of time in the look. This is why in some cases I will leave injection marks if it fits the dented look. Otherwise I just try to weather it in other methods.

BK

Good point!  It is sort of like weathering.  Some models want to create something clean and perfect, others prefer the weathered look.  But weathering is easy to do- putting wrinkles and other flaws is not!

The B-52 is maybe the best example of your problem.  When it is on the ground, the sides of the fuselage are horribly wrinkled.  Sure, it straightens out in flight when the wings tighten that area up, but if you are displaying it sitting on the ground, the real one would be wrinked.  I suspect the mfgs believe we want it to look smooth and perfect.  I think it would require a big movement among modelers asking for realistic surfaces to convince the mfgs.

Same thing with panel lines.  There I believe the mfgs are in step with modelers.  Most of us seem to want these lines to be very prominent, even overscaled.  At least that problem is getting better.  So recent kits have very fine panel lines- depends on whose kit.