The usual process seems to be to have an optimistic release date, and then follow through with it, even though Beta testers would say it could still use a few more minutes in the oven.
Then the ravenous playerbase descends upon the product and immediately discovers the same glaring issues that the Beta testers have been aware of for ages, as well as a slew of new ones by virtue of effectively being millions of Live post-Beta testers.
And then Blizzard’s over-worked, over-crunched, and over-stressed employees squeeze the last bit of life essence out of themselves to work on a slew of live hotfixes for the first week or two, whilst they’re simultaneously working on a minor patch to address some of the glaring design flaws that’ll be deployed within the first month.
After that the state of the game is usually back to a form of normal as players begin getting impatient about the wait time for new content additions.
If it’s any different this time it’s because there’s Early Access, so the player critique, nay, the paying customer anger is likely going to be through the roof if the expansion releases in Early Access with some glaring issues that impede the gameplay. Let’s hope that doesn’t happen.