I would not say Battery is allied favoured map. With some normal defence from axis, it is hard to win as allied. It is actually same concept as frostbite (2 front entrances, one open/one closed, one backdoor entrance). Axis also have backdoor benefit because they spawn at command post even if its not built there. So they have that spawn easily. And in front, the ramp is destroyable and can be maintained with 2 covert ops easily and the door entrance has ladder that is easy to camp. Would say that this entrance is uneven when its a ramp but you can climb ladders one-by-one and you cannot shoot when youre doing it.
But I think people are playing the map mostly wrong on both sides because they are used to with regular battery and that makes map derpy.