The Soviet player would be hard pressed to win the game in just 44 and 45 because the mobility of the Red Army will never match the Wehrmacht. The rate of advance to the west in the latter game will not match the Axis move to the east because of the relative levels of mobility. The Soviet tank corps are so brittle that to defeat the Axis requires more of a pounding approach by rifle corps. 1942 really is the pivitol year in a GC, assuming the Axis player does not deliver a knockout blow in '41. If the Soviets lose too many units in 1942, then come 1943 the Germans have 4 million men in their active ranks and the panzer pools began to fill to overflowing as German AFV production #s increase. Deep Axis fort lines go up, panzers assume a reserve posture and at that stage the Red Army hammers away and tries to get as far west as it can. But at the same time, the Soviets are often exhausting their Admin Points pool to replace rifle division losses. They are also dealing with reduced arms flows, as the arms multiplier was reduced to 1.6 from 2.0 and the manpower pools are also cut back to where they were previously. And all this time the Soviet player is trying to modernize the army to a corps structure, adding the needed SUs, etc., upgrading aircraft becuase the AI does a poor job of doing so, etc.
Today the Reds getting to Berlin in 1945 seems more and more a fantasy against an Axis player who has a good amount of experience.