first question you have to ask yourself is if you are going to play “fall blau” (german attack accross the donbass to stalingrad), The city itself (german offensive, where they have to take everything to win), or “Operation Uranus” (soviet encirceling counterattack)
“fall blau” would be pretty straight forward, with a few victoryareas. Depening on the scale and focusareas, good VCs would be Voronez, Grosny (or Baku), Stalingrad, rostov and/or crossing volga.
If the city itself, then taking every beachhead area and some key positions like the heights, the tracktor factory and red square would probably be good places for VCs. each unit should probably have very high move in this scenario, as long as they pass through friendly controlled terretory.
Operation Uranus could either be just about the city, or about trying to trap both armygroup A and B.
Completely surrounding stalingrad or taking it would be very important in these scenarios, kicking out armygroup B (or A dont remember) from caucasuss would also be good. in opeation uranus having supplyrules is a must.