However, that would not particularly change very much, and would not really prevent Soviets from abandoning the south. In order to try to demonstrate this, I am basically not using the reserve, other than for a small number of units. Instead, basically all of the troops in the Southwestern and Southern fronts are abandoning the south by using rail transport, rather than using the reserve functionality:

I am sending some low morale tank divisions to the Transcaucasus. Once they arrive, I will pull strong Mountaineer and Infantry divisions with higher morale to the map to replace them.
However, the low morale tank divisions I am sending to the Transcaucasus include at least as many low morale tank divisions escaped from the Western Front (and also from other places in the map like the Caucasus). Insofar as I am sending tanks from the south there, it is actually mostly ones from the Southern front, not the Southwestern front, because most of the Southwestern Front tanks have decent morale (and experience). So I want them on the map, and they are being railed to safety rather than using the reserve mechanic.
Here are the tank divisions that are headed to the Transcaucasus:


















