It could be MORE in depth if you wanted. Nothing ATG cant do that WITE can. Perhaps factory evacuation cant be done, but ive always thought that was silly in WITE, shoulda happened automatically when towns are captured, instead of the soviet player being able to Robinovich and clear his entire factory base to siberia and ignore moving troops forward.
What atg does is allows the germans and the soviets to pick their production and upgrades, where WITE pigeon holes you.
Itd be tough, but many specific unit types could be researched and added, slightly tweaked for balancing. I think certain monolithic pieces of equipment should make an appearance. The vaunted Ju87 stuka, and its various versions should be represented, as should the Tiger, KV series, T-34, Pz38t, He-111, IL-2, La-7n, and Me262/Ta-152.
These weapon systems went above and beyond the call of duty, and were much more effective than thier counterparts world wide.
Also since you have production and research, some wastes of your production and research should be available too. Nuclear research, synthetic oil research, super, super heavy tanks, .... germany should of course be able to upgrade the kriegsmarine even though thats pointless. Stuff to distract the german player.
Though to be fair, the one thing people leave out of the Russian - German war, is the naval action in the black sea. Though the scale makes it hard to replicate, since it was basically soviets in fishing boats playing pirate, and german patrol craft and submarines...but if you ask me it was the most interesting naval struggle during the war.