There simply is not enough time on the international calendar to have the World Cup every 2 years with European Championships and the like. 4 years is what it has always been an probably always should be.
Yeah, as Kingy said, there's no time, the clubs are already whining about that their stars have to play for their NT's so much, and the players are complaining that they play too much overall.
And the interest for the WC would drop, one thing that's so special about this tournament is that it's so rare arty:
Playing it too often would take away a lot of prestige from this wonderful event :scared:
If you take the case of Japan and SK, they have only just finished the stadium building scheme required for this summer. Its like the Olympics, it takes a lot of organisation. Four years worth in fact. Evey two years could risk making each one less special.
However, scrap the european champs and the copa america, and its an interesting proposal. You could award world cups to nations earlier to give them more time for preparation.
The worst time in life is just after a world cup has finished. Its painful knowing that the next one will be in 4 years....:depress:
Hope the people at FIFA realize they shouldn't mess with a thing like the World Cup. Keep it as it is. It is great and waiting for it is ok too because there are other tournaments (euro. championships,...) that keep us going.