No real explanation has been given as to why the game was delayed. Also, if you were planning on importing the special DS Lite bundle with Winning Eleven (which we all know you were going to do) be prepared to wait. They delayed that as well.
The US release date is still sometime "early next year," but who knows. We wouldn't be surprised to see that get pushed back into something like "Halfway between Summer/Fall/Winter -- doesn't matter, your waiting."