First look at the frontline at the end of AO43. According to the plot, German troops were barred from any attempt to attack Stalingrad again. While we the players have achieved great victories in the Caucasus area, it didn't mean the southern front is in good shape. The front line is extremely long and the mountainous terrain of the Caucasus area means occupation of this area very difficult. In the south there are British-occupied Persia, even though we have defeated them in operation corridor and managed a successful raid in Tehran region, it will not stop the allies there forever. Hence a huge force was needed to secure the area.
And secure it must be. Afterall the whole point of the Caucasus campagin is to capture this oil rich area to fuel German's war machine. Oil facilities and pipelines are vulnerable and obvious targets that must be protected by enough garrison, heavy AA and even Luftwaffe against partisan, Allies air raids and potential Allies counter offensive from Persia. Losing Caucasus oil fields or letting them be destroyed is politically and militarily unacceptable.
Simply put, Caucasus was a huge resource drain. So it is not difficult to imagine that OKH has to scrape all available resources from AGN and AGC to secure Caucasus.
On the other hand, without securing Stalingrad, it is impossible for Germans to start any offensive from the south to the heartland of Russia. The poor infrastructure in Volgograd and Voronezh regions didn't help too. So for the Soviets, with interior lines advantages, they can keep much fewer troops in the southern front and redirect their focus elsewhere.
With the Western Allies failure on D-day, they must have to shift their focus elsewhere. Attempting to land in Western Europe again is not a good idea, at least for now. Their first priority is to resupply the Soviets to keep them in fighting shape. Without major land operation in Western Europe (Italian front is not a good theatre for major breakthroughs due to geographic restriction), the Allies can put more naval asset in escorting the Arctic lend-lease route and provide more land supplies to the Soviets, to compensate for the loss of Persian route.
Putting these pieces together it now makes sense to me why after all German's triumph in the Southern front, the Soviets decided their first move was to knock Finland out of war and start major offensive in the north. With interior lines advantages they can concentrate their force in one front while the Germans have been stretched extremely thin. An offensive in the North can be well supplied by Allies lend-lease resource. Knocking Finland out of war and lifting the siege of Leningrad provided a morale boost that the Soviets desperately needed.
The follow-up grand plan of attacking Hungary and Romania to cut Caucasus off from mainland is a little bit ridiculous though... The scale of such an operation is too huge to be well executed. But still, I love how things developed in AO44, it is not an alt history scenario that I usually read/see, I appreciate the creativity and thought in the plot. Can't wait more for AO45.
