These levees broke hard. The information pouring out of various game sites is fascinating, and we're watching keenly for the choice parts. For example, IGN's exhaustive coverage mentions that "your own actions can begin to have a lasting impact on the game world." Storytelling is clearly a critical aspect of the SWTOR approach, and we're intrigued to see how the fate of the world is entangled with that of the protagonists.
Another point that caught our eye was the limitation on content: "there are places that you won't be able to go and things you won't be able to do unless you join a mixed party." Although you'll be able to bring along NPC companions (sounds rather like the way Guild Wars handles it) it's not clear whether this would allow devotedly solo players to access the group content. More news as it emerges.