There really is no such thing as an a/m... you either have better wizards than your opponent, or you don't. Being mystic makes this much easier, but rune supply is always problematic for any attacker. Late age, any province that is still small and didn't have their wizzies targetted is going to have good wpa, which makes attacker-mage against those provinces very difficult no matter how much WPA you pump.

Best to wait on final changes, but there are some things which remain constant from age to age.