The conventional wisdom in prior A&A games was for Germany to buy inf/art for the first few turns. So alot of the early strategies aimed for an attack on Moscow on G8 or G9 (these players built artillery for a few turns and then built mech, creating an invincible but not particularly mobile army)….which gives Allies more time to make gains in other regions or retreat the Siberians. Alot of times the Russians could simply abandon Moscow on R7 or R8 and still win the game if Allies were doing well in the Pacific.
Another factor was that in prior games the conventional wisdom was that Axis needed to move quickly and decisively to win the game while the long game favored the Allies. It took us awhile to figure out that (with the help of National Objectives, dual victory conditions and map dynamics) Axis could win the long game without having to capture any Allied capitals for the first 10 turns.
It took alot of us awhile to realize that J1 and J2 were generally better than J3 (although this shouldn’t have been hard to figure out given the superiority of J1 in the standalone Pacific game). This is closely related to the fact that most of my early games were Sea Lion games (so waiting till J3 keeps USA out of the Atlantic). Allies generally have a better chance in a Sea Lion game than in a Barbarossa game.