He clarified quite a few things from the reveal video and discussed some mechanics that will carry over from Guild Wars, such as the ability to dodge.
Some new information on the blind condition caught the attention of quite a few fans. Rather than the timed duration we're familiar with now, blindness in Guild Wars 2 "causes the target's next attack to miss."
Interestingly, a question very near the top of the frequently-asked list was not answered: that of interrupts. There's heavy community speculation on why this is, and hopefully we'll have some news that clears it up very soon. For now, the latest round of new information can be found at the ArenaNet blog.