Also while Sydney was away, Sloane actually assembled the Rimbauldi device. He said it was constructed to play a one word message "Peace." Sloane is now the CEO of an organization that feeds hungry children. Sydney isn't buying into his total reform.
...and of course there's the whole story line of Sydney and Vaughan! Two years of lost memory only to wake up and find out that Vaughan is now married to someone else and isn't in the CIA anymore, now he's a teacher! I LOVED the scene at the end where Sydney tells Vaughan off ..."It's all about faith. You and I have seen some pretty unbelievable things together. I'd have never given up on you, what a complete waste that would have been!" (I probably didn't get the quote exactly right but it was a great scene.)
Then there were the previews.....lots is going to happen this season!