I appreciate your comments and input Joshh. Your right about the lack any type of detail on the tanks. That is intentional. Everything you mentioned I ultimately plan to get around to. My goal right now though is quantity over quality. Personally, I find it impossible to play with anything that hasnt been painted to at least the standard you see above; however, I just dont have the amount of time needed to dedicate myself to the detail yet.
The tanks themselves do have a pretty good amount of detail and color tone differential like you mentioned. I think my camera does an excellent job of hiding much of it with its flash. When I paint though it is subtle and gradual and builds up....so most of it require you to stare at the tank closely to see it

I did add shading in all the cracks and crevases, a very time consuming and exhausting task, but again, subtlety is the key.
Finally, if you look at any of my Blood Angels pics (and I have a bunch of them on this site) you will notice there are no metallics on my characters or vehicles. The tracks on these tanks are a combination of greys and washes. My goal is to build up my
NMM skills and return to these projects and finish them off with a gorgeous
NMM finish. But that is in the very distant future.
Thanks again for the comments!