It looks like the predictions that South Africa will be a repeat of the Korea/Japan '02 attendance disaster are coming true already:

Official attendance for the Greece - South Korea game in Port Elizabeth's 46,000-capacity stadium was 31,513.  

Korea/Japan were literally giving away hundreds of thousands of tickets for free and they still couldn't get their stadiums more than 2/3's full.

Should FIFA take attendance more into account in its future allocation decisions? Or does hosting the tournament in new countries to spread the sport's popularity take precedence over actual attendance?

It seems pretty unfair to me to host the world's most popular sporting event in places that are too far away and too difficult for most of the world to travel to.