Blizzard just ended speculation that the two pre-Cataclysm world events
for the gnomes and trolls, Operation: Gnomeregan
and Zalazane's Fall
respectively, have entered "stage 2" and are no longer available for players to complete. Here is the official blue response:
Re: Operation: Gnomeregan
I don't see it in the 4.0.1 patch notes, but it's been in the 4.0.1 PTR.
Is the next phase of Operation: Gnomeregan going live today as well?
The next phase does start today, but it's a passive phase. There will not be anything for players to do outside of Gnomeregan, or on the Echo Isles, until the new bases of operation for gnomes and trolls are complete, and the new level 1-5 starting experience is added in patch 4.0.3.
If you missed either of these two events, it looks like you're out of luck. As mentioned, the new leveling experiences for trolls and gnomes is coming with patch 4.0.3.
This is it! Patch 4.0.1 begins the slide into December's upcoming expansion. It's a whole new game from here on out. Get oriented with our roundup of everything there is to know about patch 4.0.1 and how it changes the game until the launch of World of Warcraft: Cataclysm.