What's not explained (so far, likely because no one's able to get that far yet) are how the night elves play into the whole worgen "thing" as shown in the Cataclysm trailer, but there's still a lot of new information on phasing, quests, and scenery in Gilneas besides what we've already covered, as well as accompanying photos. It's definitely worth a read.
Hopefully Blizzard will continue to fill in more blanks in the worgen storyline as we get closer to the expansion's release, or maybe even update the Cataclysm site more than once every four months. In the meantime we can rely on sites like Scrolls of Lore to give us exhaustive previews of public demos like this one.
World of Warcraft: Cataclysm will destroy Azeroth as we know it. Nothing will be the same. In WoW.com's Guide to Cataclysm you can find out everything you need to know about WoW's third expansion. From Goblins and Worgens to Mastery and Guild changes, it's all there for your cataclysmic enjoyment.