These rankings are completely meaningless since the vast majority of people will never holiday in all these countries. And even if you're an "every country" geek like some FTers, you're more likely to just get a visa than a new citizenship.
A better ranking would be the number of countries you can move to and work/live with a minimum of hassle. Then EEA passports would probably win, but on the other hand, the US is a single country which is arguably nearly as diverse as the EEA.