I know that many have said that more soccer is a good thing. But I think with the talk of moving to more teams is not that great. I'm pretty sure that most of this is said by Hagbard above, but I must share it:
This tournament has balance. The groups are weighed really well. The great teams don't all get cakewalks, and generally every group has a few matchups that see teams pretty well matched up. Getting out of the group for most teams is an accomplishment and for most, can't be taken for granted. Sure, you sometimes have a group that is just has a team or two that is far and away better than everyone else, but in most cases, they are not.
Getting in isn't automatic. The qualifying has drama. Look at this year, we had Italy, the US, Chile all miss out on the last day of qualifying. Good teams miss out. It means something to get to the World Cup. You add 16 more teams to the mix, you're just making sure that all the good teams get in and frankly getting in won't mean much at all.
Hagbard's right, they don't have to make the change - hope they realize it's a mistake.