World of Warcraft: Cataclysm Q&A

Wired.com has posted a lengthy Q&A they did with World of Warcraft: Cataclysm lead content designer Cory Stockton during last weekend's BlizzCon event.
Wired.com: For people who are nostalgic for the old world before Cataclysm, is there going to be some way to revisit Azeroth as it was before?

Stockton: I think that's what Caverns of Time is for. We'll definitely have the ability to do that kind of stuff, but we are also going to do a huge world event leading up to the Cataclysm. Some time after patch 3.3 and after (the Lich King) Arthas is defeated, you'll definitely see a giant world event that affects the Alliance and the Horde very, very much. It's going to change everything for them. It's probably going to last something like a month. Something similar to the zombie invasion before Northrend. It will be something that will roll out slowly over time. But we are planning to do a huge world event, so everyone will know the Cataclysm is coming.

Wired.com: Does Cataclysm affect the old world achievements?

Stockton: Definitely. We're going to have to go back and look at those achievements because certain things might not be available anymore and there are also going to be new things that we're going to want to add. So definitely it will affect that stuff. (Old world achievements) will be converted to (Feats of Strength) (achievements that don't add points to your player score). So if you have one, for instance, and we removed that from the game, we removed the ability to get it, but (in your list of achievements) it will just become a Feat of Strength.