I want Argentina to win the world cup, and I wouldn't be bothered at all if England didn't make it past the group stages. However, it sucks that things like this have to happen. The world cup SHOULD feature the full strength squads from all the countries. With something like this Rooney injury, the balance in the England squad will be messed up, and things like this aren't good for the world cup. The best players in the world should be playing in the greatest tournament in football, and it just sucks when they have to get injured before it begins.
Why doesn't the world cup start at the beginning of July and end in August????? This would give players plently of time to recover from post-season injuries, and would give the national sides more time to practice together and get friendlies in. Club managers probably wouldn't be too thrilled about this idea, but you know what, the damn thing happens once every four years. I would be all for having it pushed further ahead and seeing all the squads fully fit than having it 3 weeks after domestic seasons end and having players like Rooney and Owen doubtful.
As far as player fitness goes, if you're about to represent your country in the World Cup, you should not need any more motivation than that to stay fit. So don't even give me the arguement that beginning of July is too long and players wouldn't be in shape.