The S.America thing seems odd but they do only have 10 nations. I was thinking they'd get 2.5 more, but even then that would mean 7 out of 10 qualifying.
Considering the 7th ranked team in comnebol (Ecuador) is ranked 20 in the world this is probably fair. The problem is that qualification could be pretty dull. I think the way to make it more interesting is for 2 teams from each confederation to go into a two legged payoff for the last six spots. It gives each confederation more potential spots, but the teams will have to earn it.