Indeed, I think there are some fairly potential far-reaching consequences for this scenario. As to how they might achieve such a penetration is something else entirely I guess.Theoretically they could have an ephemeral penetration and then things converge with OTL. The Germans don't move as much force from west to east. The extra force in the west does not suffice to allow Germany to win. The A-H'ers reverse and contain the breach before any other powers get in.
But that is kind of boring. Other consequences might be an earlier entry of Romania into the war and longer Serbian survival, or the Austrians dropping out for a white peace.
Indeed, I think there are some fairly potential far-reaching consequences for this scenario. As to how they might achieve such a penetration is something else entirely I guess.