WotC was put with a HARD choice. They're initial plan was met with happiness from many, but also a LOT of outcry, anger, and unhappiness.
The problem has already been outlined. The distribution method made it so that those who did NOT have access to the gaming stores but wanted a copy were out of luck. Even worse, many would probably obtain a copy but at HUGE mark-ups from those who were lucky enough to be near a store.
With the demand from others outside the hobby store network being so high, and people being so unhappy who were not in the network, what would you have done?
The ideal would be for the original plan to work, but everyone to be able to pre-order their copies through those stores. Unfortunately, that didn't seem to be working overall.
Hence, I think it was a VERY difficult choice on what to do.
However, just because it's listed on Amazon does NOT mean it's going to be available on Amazon the day that it is available in the hobby stores. I think the date is still pending if it even comes to Amazon in the US.
But overall, making it available to those outside the US by other channels wasn't an easy choice, but I think overall the right one. It makes a LOT of gamers happy and makes them know that they are not forgotten or taken for granted.