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And the reason you state is precisely why. Risk is simpler...fewer things to consider. Axis and Allies you can only convoy things so far each turn, so you have to place your assets even more strategically. Also, you can either spend money on sheer brute force, or you can invest in game-breaking technologies, but each investment costs money whether or not you actually succeed on the dice. On top of all of that, Axis and Allies makes you think about more different types of warfare units and gives them realistic strengths and weaknesses, so simple frontal assaults don't usually work very well.
On the risk board, my strategy always focuses on South America and Australia. In Axis and Allies, you can't pick a single winning strategy.