I would be much more pleased to have a system where:
Axis gains an offensive bonus in homeland (useful in defensive counterattacks as well, though a better representative of the typically revanchist/nationalistically expansionist attitudes of the regimes).
Does the Axis really need any inherent combat bonus just for being the Axis though? If it's just to make sure there's a nice early advantage for big gains at the start of the war starting tech values and the high consumer goods needs of the Allies should be enough.