Is D2:ED finished? The publishers require a bit of lead time to do some advertising and get some English reviews, etc, so Larian could be taking the opportunity to make additional changes or additions to the game (over and above integrating the 1.02 patch).
Since the UK and Australian English publishers have not been announced yet, the North American publisher can not really set an exact date (presumably they would want all English versions released simultaneously).
Even if they have a specific target date, they may wish to leave some flexibility so they can adapt to changing situations (marketing responses, other game releases, etc).
