So is it too early to consider the lessons for the world cup and how they apply to US soccer? I'll take my swipe:
1. The possession game: when Spain won the World Cup everyone rushed out to copy it. But I think the world cup has definitively shown that possession for possessions sake doesn't always get the job done, with Spain scoring a record for possession but being routinely unable to penetrate.
2. The high press: The legacy of Germany's victory still plays out. The high press is an effective means of countering the possession game, and forcing errors upon the keeper/defenders, as Croatia showed.
3. Negative soccer v. the English long ball: But I don't think a definitive style came out of the world cup that other teams will try to imitate. France played a very negative game, relying on possession, but also relying on a fast counter attack. England on the other hand played a long game focused on set plays. Most of their goals were off of direct kicks or corners, which is something US coaches don't spend a lot of time on particularly on the lower levels. Sure, you can say England was on the weaker end of the brackett and lost, but they also have had success in the U-20 with the same style. France is also more academy centric (which is why they were able to incorporate and nurture their immigrant style), while England's youth soccer is organized more like our AYSO and rec leagues where everyone can play and talent is identified later.
4. Headers: Heading was very important in this tournament. Might we play a price for our pushing back the introduction of headers due to concussion concerns?
5. Defense/Offense: Second tier teams were often able to frustrate possession game teams by emphasizing their defensive back line, including the Spain v. Morrocco game. While its a problem worldwide, the US doesn't give as much emphasis to training defenders (where the most athletic kids drift the glory positions of 9 and 10). Similarly, teams like Argentina and Portugal that relied solely on their one world class striker weren't able to advance very far either.