Cruzz I don't really get why you think guards are the only option. They are pretty niche after the patch. What do you have against shocks, and why is the IS2 not effective?
1. Because they're in the only competitive commanders that have mark target and mark target is practically required against axis heavies in team games
2. Because shocks are extremely easily abused by all sorts of vehicles and are useless on half of the maps in the game. Their durability also drops off very rapidly towards the later game because most high damage small arms have higher than 1 penetration nowadays.
3. Because the IS2 is plain bad against OKW, all their vehicles are custom designed to abuse the weaknesses of the IS2. And Ostheer Tiger with PaK support is always superior to IS2 with ZiS support as well.
4. Because if you don't have guards you are relying entirely on ZiS for anti-tank, which is a completely unsustainable arrangement manpower wise on any map that allows for relatively easy light vehicle flanks.