As stated from a Blizzard rep (“One of the Blues”) on another post:
Now in regards to -
As of yet, they actually don’t have a set date for the physical collectors box edition; nor an estimate, so stating ‘till Spring / Beta Starts’ is ultimately inaccurate.
The others in the past have had various release dates in terms of timeline with the testing of the given-expansion etc. Although I would not be surprised if they did release it sometime when or shortly after the beta starts.