I agree that April seems waaaay too early, especially given that they've said they'd post a release date 2 months ahead of the release. What about Jay's tweet that can't debunk or confirm the Italian website's date, though? Also, beta patch 13 was pushed on the 18th of February, and if Blizzard released that patch knowing that it'd be the last one, it's possible that they've already started pressing DVDs.
They've mentioned in the past that they want to run the release the same as WoW's Cataclysm, which allowed players to download the client so they could run it when it launched at midnight. This would allow for last-minute, minor patches to be applied as well, so if the game's 98% done at the moment, that could be a way of getting out that last 2% without making the fan base wait for manufacturing time. As far as printing boxes/box art goes, that's probably been finished for months.
So, IF (and that's a big IF, keep in mind) some or all of the outlined scenario is true, April 17th or shortly thereafter could still be a viable possibility. Again though, the only reason I'm personally compelled to engage in this much speculation is Jay's mysterious tweet... they've been so quick about crushing release date rumors in the past, so why not "debunk" this one...?
Edited by Zhaph, 05 March 2012 - 04:31 PM.