What I like about the explicit rotation:
* more transparency, the rotation is no longer an unwritten rule;
* more time (2 years) to make Wikimania great, less volunteer time spent
on (concurring) bids;
* more concreteness and (hopefully) cooperation in the selection stage,
less "let's beat continent X";
* more pragmatism, recognising we can't always flight the biggest groups
of people in the farthest places.