Patch 2.3.3 went live yesterday, and it shouldn't have.
While I personally didn't suffer much in the way of grief (well, things did seem a little laggy but I have nothing solid), some people were suffering endless DCs after the "upgrade".
Our GM, on her healer alt, died multiple times in Steam Vaults because of this. Steam Vaults! Especially on the final boss - losing your healer midway through is one way to get your head danced on.
So looks like we're setting the stage for a 3-day downtime for WotLK, eh?