Welcome to the boards?
I would disagree and say they
(the previous expansions) didn't roll out flawlessly, but there were not a large amount of issues that prevented people from playing on a large scale.
On the rational of expecting Blizzard to fail, Blizzard has had a steady pattern of failing on larger and larger scales most recently.
Take the whole Blizzard Store Fiasco, people have gone literally over a month with their credits cards being charged, and not so much as a "Sorry" for not delivering the merchandise.
(No, I do not count a handful of badly spell checked e-mails and a vague blue post on the odd-ball forums as a sorry, or even admission of guilt)
Blizzcon '08 ticket sales? Yeah, need I say more.
Recent Shattering patch? or even the past few large patches before it, servers were down for nearly an entire day. I know between my own personal schedule I was not able ot play at all that day, but was greeted with a working server the next day.
I remember the patch that was so bad and took so long to get the server up, Blizz gave everyone with a subscription a 3-day free credit.
I don't think it's outrageous to expect failure, or at least problems when thats mostly what we have been seeing for quite some time, especially when it comes to large scale happening with the game itself.
Furthermore, it seems rather holier than thou for you to say for certain that there will be no problems.
Certainly it's possible, and not a single person around here is
HOPING for failure, we simple expect it, and are fearful of it.
Like with all things in life, if you don't like the way Burger King makes your burger, go to Wendy's, if you don't like people going on about how the X-Pack release will fail, don't read the posts.