Any league that uses an Adidas ball can have access to it early. Hardly the fault of the Spanish (and whoever else) that the Premier League chooses to use Nike balls is it?
I seem to remember that happening at the last wc too. It does seem a little unfair but that's the PLs fault (again) for their commercial deal on the ball they have to use.
World cup holders so they get to play with it 6 months in advance, happens in all sports. same with Wimbledon tennis, andy murray can practice with the tennis balls they are using at this years event.
We have so many foreigners in the Premier League it probably has a disadvantage for most of the nations taking part. Then again, it's like any football, it's round and you kick it.