I am writing from the point of view of an Axis player. I have played numerous games at this point, some against experienced opponents. I feel that I have a pretty good take on how to act offensively and quickly as Axis. But in many games, one success has frequently turned bitter. That success is my 41 Leningrad strategy.
I normally give AGN 75% of the infantry reinforcements, but I do not reinforce PG 4. Being focused and precise, I normally go straight to Pskov to the Neva to Isolating Leningrad. With speed and grinding tactics I have been able to take the city and, more importantly, chase the soviet back to Cherepovets.
This success has been the cause of my problem. Once the soviet decides to give up the north, they have in multiple games really given it up and fallen back to a very strong line way way to the east. Since it makes no sense to ever counterattack here, this area gets a minimal garrison. I have seen other AAR's where the soviet has taken minsk later in the war while the axis is not that far from Cherepovets.
This give up by the soviets in the north then allows a lot more units to be assigned to the south in 1942. I would like to point out that finnish units get hammered from a morale perspective if they stay for any length of time out side of the no attack line. I would also add that giving up the north in 41 allows the Moscow front to be reinforced as well.
Since a really good Axis 42 offensive is needed to put the soviet into an AP crunch and delay the creation of soviet army 2.0, does too much success in the north actually hurt the Axis? I would really like to see many soviets on the volkov line and fighting in Karelia during 42. It takes much more effort to garrison the north so the axis cannot attack there if the front line is near Leningrad. Of course, this would make any southern 42 axis offensive easier. Also for the mid and end part of the war, AGN offers really good defensive terrain all the way back to Riga, so you are not really giving the soviet any easy route to berlin.
I now think that too much success in AGN is bad grand strategy. It may almost be worth it to isolate but never take Leningrad if you could be sure of re-isolating the city after blizzard has run its course. If you win in 41 it does not matter, but if you need a strong 42 axis attack then maybe less success in the north is a better result.
Food for thought atleast.