Agreed! There's often a little jostle during the starting land grab to get Australia: easy to defend and those extra reinforcements really matter in the early game.

Australia and South America, because Australia can be defended in a single territory (Indonesia), against a single territory (Siam) and South America can be defended in two territories (Venezuela and Brazil), each against a single territory (Central America and North Africa respectively.)

In South America, you can get lucky and take North America in 1 or 2 turns. Since North America shares a front with South America, you end up with the same number of fronts you would have if you possessed North America alone, and in a very defensible position. The fewer fronts you have, the more interior you have that doesn't need to be manned with troops.

Yeah in my experience whoever starts in Australasia basically always wins because it's so easy to defend. Risk is a pretty terrible game by modern standards anyway.