First of all; at the moment there is no product to use. You can use the product on Thursday, when it goes live. No need to panic.
Yes, streamers and reviewers have a review build to play at the moment. That is standard procedure for any game. Nothing to whine about.
Indeed, we all wish to preload the game, and you will have that opportunity today. Brandon Adler stated in another thread they will push out the keys today (they're on pacific US time so that might mean tomorrow if you are in some other time zone).
And people taking their day off on Thursday is just peachy. They will get to play the game when it goes live, which is 9 am (PDT) on Thursday (again, according to Brandon Adler).
Seacrest out.