I think they are leaving themselves a lot of room to maneuvre with the simple points promotion system as it's been outlined at this stage. If it turns out that more people are flying the Allied rides, they can always bump the promotion points up for the Axis side if they feel it's necessary. The point thing also allows them potentially to scale some of the missions, so that a really dangerous mission (attacking B17 formations in a 109E

) provides greater rewards and potential for promotion, as in life.
But there will be a long break-in period for this. Allied rides tend to be more popular in the scenarios and TODs because of the demographic of AH, but also because the snapshots, scenarios, etc., are only occasional events. If this kind of thing is happening all the time, it actually provides a much greater incentive to try alternatives and swap to the other side. It will probably be much more like the CT in that respect, where side-switching for numbers, or just to play with new equipment, is common.