They set up Dan Steven's exit from the show, which is officail according to news stories all over the net today. I think this will end up being good news for Allen Leech, who plays Tom Branson. His character had a lot of good screentime last night, and I would bet he'll be a more central figure next year.
Other than Matthew's tragic exit, it was good news and warm moments all around for the rest of the family and staff. They pack up and visit "Cousin Shrimpy" in Scotland, and they become more grateful for what they have after seeing how miserable life is for Shrimpy and his wife, and daughter Rose (who has already appeared in the last couple of eps in S3, and will apparently become a regular in S4).
Mrs. Patmore had a funny story about a male suitor, Edith's relationship with her publisher grows deeper and more complicated, and Thomas can't help getting his ass kicked again. But it leads to an interesting scene between him and James... O'Brien has some non-villainous screentime, and surpise! Mosely gets drunk again.
As for Tom, he stays behind with the baby at Downton Abbey, and is faced with running the house, and being fully catered to by his former friends on staff. He grapples with how he has changed since becoming a member of the Crawley family. Also, there's yet another new maid looking to suck face with a Crawley. Luckily this one dooesn't last as long as Ethel or Jane -- that story has been done to death.
But overall, I was glued to the screen from start to finish. Can't wait for the S3 Blu-Ray to be released...