If this was Blizzard they would have extended the release date OR, more likely, pulled the plug on it all together.
From what I remember of WoW, there are several unfinished areas you can glitch yourself into, or at least you used to be able to.
Examples that come to mind: Old Ironforge and the airfield above the mountains. I've seen a couple other areas in other zones too.
And unfinished quests and other content.
Take the smiling John or Jim (where they burn down his bar) quest for example, I don't remember them finishing that quest, which came out at launch wasn't it, until around 2 years later. And how many other quests, from launch, seem to just stop without a resolution. And how many times has Blizzard gone on about how they'd absolutely LOVE to get this old, meant to be out when game launched content finished, but well we just have to put out the next expansion to make more money?