What if the German's made Leningrad ( and by extension Murmansk) the primary focus of the 1942 campaign?
Let's say Hitler is convinced that the oilfields of the Caucasus will never be captured intact. Instead, he resolves to push the South front forward enough to bring Maikop/Grozny into luftwaffe range and has them bombed to deny them to the Soviets. Baku is still out of range though.
Meanwhile, the main summer offensive goes off in the North, aiming to capture Leningrad, link up with the finns and threaten/cut off Murmansk.
How would things go for the Germans? Better or worse than OTL?